I picked this up for mountain biking, and it's a great size and fit for the task. Good amount of space for a full day out - water, extra layer, snacks, tools, etc. I think the 20L size is really a sweet spot for me in that it has enough room to carry a few extras if the weather is dicey without going overkill. Also, the suspension is great - the back panel is curved outwards slightly, so it leaves plenty of space for air to pass through. My gripe with this pack is that there are so many pockets that it can be hard to figure out where your stuff is. There is a large main compartment with water bladder sleeve, small sunglasses/ cellphone pocket, and two accessory pockets with mesh organizers for all your tools and smaller parts. The problem is that all of the pockets are stacked right on top of each other, with all of the zippers right next to each other. I find that I almost always end up opening 2+ pockets before I find what I'm looking for, just because everything is so close together.
All in all this is a great pack for its size - nice features and really comfortable for riding, I just wish they simplified the design and the zippers.