This is a tough review to write as there were many options and I had some conflicting goals.My initial expectations were probably a little unreasonable. What I wanted.....1.) The smallest depth possible so I can ride a chairlift with the pack on.2.) The absolute minimum of compression straps and other straps to minimize the chance of snagging on a chairlift.3.) The ability to carry 2 pair of skis from the car to the lodge.4.) A goggle pocket that will hold my big, spherical lens goggles and 2 spare, quick change magnetic, lenses for changing conditions.5.) Hydration bladder compatibility even though I'll likely never use it for skiing.6.) A pocket for the stuff I'd ordinarily carry in my pants pocket.....car keys, wallet, pocket knife, change, a small Canon Elph 360 camera, iPhone7.) Room for my lunch.....typically a sandwich, bag of chips, piece of fruit, candy bar.8.) Room for a beanie, spare gloves, and a top layer in case I want to shed some clothing.9.) Good looks10.) The whole thing had to be easy to use and ski with.That's it. I wanted a pack for in bounds skiing to make life easier. I'm not looking for a pack for back country skiing. I just don't want to walk back to my car or go into the lodge to swap the lens on my goggles. I don't want to pay $25 for not so great lodge food for lunch. I don't want to hike out to my car with ski boots on to get my lunch. I usually bring 2 pair of skis with me. I wanted an easier way to carry them back and forth to the racks by the lodge. I'm also wary of leaving an equipment bag in the lodge unprotected all day. My equipment bag is big and heavy and having your stuff stolen is no fun.I looked at a bunch of brands and individual packs and quickly came to the conclusion that Dakine was really the only company out there who caters to the needs of skiers. The problem then became the fact that Dakine makes a lot of different models from 12 liters to more than 30 liters with a mix of features.I was focused on the Heli Pro 20 liter at first because it has A-frame and diagonal carry options. But then I noticed that it's 8 inches deep. That would eat up too much space on a chairlift.I also looked at the Mission Pro 25 liter. But it's getting big for in bounds skiing and it's 7" deep. It also has only diagonal ski carry.I also looked at this Heli Pro 24 but it's also getting big for in bounds skiing and Dakine / Amazon make no mention of a hydration setup. And they designed it with only a back panel access which means you have to take the pack off to get inside. A buddy can't dig out fresh gloves or a beer. Or so the product description would lead you to believe. I didn't think I was going to like the Heli Pro 24. But, it is only 6" deep.After sorting through the Dakine product line some more I found the Mission Pro 18 liter that has everything I wanted except the dual carry option. At only 5.5 inches deep, it's 30% slimmer than the Heli Pro 20. Could I get away with this minimalist pack?Price wasn't really much of a consideration as the difference in price was only about $20 between any of these packs online.In the end, I decided to order the Mission Pro 18 for its clean, slim profile and the Heli Pro 24 as my "luxury" solution to compare them side by side.Mission Pro 18 dimensions 20 X 12 X 5.5 inchesHelipro 24 dimensions 23, 12 X 6.0 inchesThe Heli Pro 24 disguises its extra capacity pretty well. It's exactly the same width as the smaller Mission Pro 18 at 12 inches. It's 3 inches taller at 23 inches. And It's only 0.5 inches thicker at 6.0 inches. At 6'0" tall I don't even notice the additional 3 inches in height. If you're smaller, say a 5'2" woman, it may feel different on your torso. And the half inch extra thickness is a non issue on a chair, especially if you don't pack it to capacity. Lightly packed, it will squish down to 4" thick.So what do you get for the extra size? Well a significantly larger goggle pocket for one. I could get my goggles and 2 spare lenses into the goggle pocket on the Mission Pro 18 but it wasn't an easy fit and I worried about scratching the lenses. The Heli Pro 24 on the other hand easily swallows the goggles and 2 swap-able lenses. And of course there is overall 33% more space for stuff.What about the downsides with the Heli Pro 24 of losing a hydration system and only back panel access? It turns out that neither is true. The Heli Pro 24 has a really nice hydration bladder pocket and and a hidden insulated sleeve for the drinking tube inside the left shoulder strap. As for the back panel access, there is also a top load zipper. So you don't have to take the pack off to access the main compartment. But, Dakine mentions neither of these features in their marketing materials. Also the tools compartment where you'd normally put your shovel, probe, and other tools for the back country is accessible from the front of the pack. So access with the pack on is not an issue.For even more upside, the Heli Pro 24 can actually carry 2 pair of skis.....one pair in A-Frame mode.....one pair in vertical mode. Ya may look a little weird carrying 2 pair of skis but it's only for the trek back and forth to the lodge.Given that the Heli Pro 24 met my two key criteria of carrying my goggles and spare lenses plus carrying 2 pair of skis, I decided to keep it and return the Mission Pro 18. However, if you only carry one pair of skis and you're not packing 2 extra lenses for your goggles, the Mission Pro 18 is a slimmer, cleaner design that will probably be a better choice on a chair lift.I'm a fairly big guy at 6'0" and 215 lbs with a 45" chest and 34" waist. The pack fits me comfortably and rides well. It's pretty much unnoticeable when I'm skiing. It doesn't shift around. It's not annoying. But I have less than 10 lbs total weight in the pack. The shoulder straps are not thickly padded but comfortable enough for the weights this pack can carry and they aren't bulky. There is plenty of adjustment for a guy my size. The waist belt is wide and comfortable enough with 4 layers of clothing.....a base layer, high tech long sleeve shirt, wool sweater, and soft shell jacket. Being able to leave the pack in place on a lift is a huge plus as even though the waist belt buckle is well designed, it's tough to operate with ski gloves on. It's doable but you'll fumble with gloves on. The sternum strap buckle is small enough that it's basically impossible to feel through a pair of ski gloves. So, if you take the pack off to ride a lift, expect a minute or two at the top to take off your gloves and put the pack on before each run. That's why I don't want to take it off to ride a lift. And with this pack, I can get away with leaving it on while I'm riding the lift.In the end, I decided to give up the minimalist 18 liter pack for some extra features and capacity but, I can see an argument for either of these two packs for an in bounds skier.One note on looks. This pack comes in several colors. All I wanted was basic black because I switch off between 3 soft shell jackets that are black, red, and orange. The black matches well with all three. But the Heli Pro 24 comes in about a half dozen colors and patterned fabrics. If you're tired of the basic black look, you can find a lot of other options. Some of those colors could be really helpful for visibility in deep powder, a snowstorm, or fog. I may add some reflective material to this pack for those low visibility conditions. I almost bought the orange version. I liked the looks but also, it's much easier to see all the zippers and straps because they are done in a contrasting color. With the black, the straps and zippers are pretty much camouflaged as everything is just black. I think the orange pack would be easier to live with.Lastly, at 24 liters with a hydration system, the Heli Pro 24 is a good size for a 3 season day pack for hiking. It will allow me to ditch my 110 liter backpack on day trips.The 4 photos below show the Mission Pro 18 and the Heli Pro 24 in front, side, and back views along with the two packs laying down for a comparison of thickness. I had them packed with clothing to fill them up to what I thought I'd probably do when skiing and the goggle pockets were holding goggles.Hope this helps you sort out your choices.EDIT 1/16/2018: I checked out my hydration bladder in this pack and it will hold a 3 liter bladder perfectly. There is a Velcro strap at the top of the compartment that can be used to hang the bladder.My 3 liter bladder is a Baen Sendi unit bought here on Amazon. It has the wide open top sealed with a clip as well as a screw on cap near the top of the bag. The drinking tube has a sleeve of neoprene insulation and a push-pull valve with a dust cover over the bite valve.I was concerned that either the already insulated drinking tube would have trouble fitting into the insulated shoulder strap pathway or, that teh dust cover on the bite valve would be too big to zip the pocket on shoulder strap shut. No worries. The tube fits fine and the hidden pocket zips shut over the dust cap.3 liters seems like a lot of capacity for a small pack like this. I'll probably never use it. But if you were wondering, it's there if you need it.Edit Fe 2, 2018: After skiing with this pack for a little over a month, I have one wish list item for Dakine, and every other pack manufacturer, to work on. Strap management. I'm paranoid about loose straps dangling from my pack and getting caught on a chairlift or a tree branch when I'm skiing. So, once I've got my gear on in the lodge and my pack is zipped up, I spend another 5 minutes rolling up all the loose straps and tucking them under the little elastic bands Dakine includes on the straps. Yes, they include something for strap management but, it's pretty cumbersome and time consuming. Throughout the day, as I take the pack off, dig through it, and put it back on, I have to go through the strap rolling ritual again. My big Kelty 110 Liter backpack has something similar but it's more like a round rubber band and much quicker and easier to use. It also keeps the rolled strap in a much smaller, neater package. This probably wouldn't concern me so much in the back country but I have visions of dangling from a chairlift by my pack straps. It's a minor design change but one that could improve safety and the livability of any pack. And with that said, one of the reasons I chose this pack is that it has a very clean design with not much hanging off of it.