Just my opinion, of course. I originally bought the Nomad to use dirt biking, and found it too small to fit all my gear. The Apex, on the other hand, fits my tool kit (about the size of a travel bath kit), spare tube (way bigger than an MTB tube), pump, first aid/emergency kit, 40ft. of 8mm static line, a waterproof shell, a long-sleeve wool baselayer, food, sunglasses and 100oz. of water. If/when I get a GPS or PLB, it'll fit in there too, no problem. The bladder system is great, thanks to the center divider that keeps it flatter than a straight tubular bladder, and I love the quick-disconnect feature for filling up. While the full pack weighs at least 15lbs, I don't find it uncomfortable on 4-5hr. rides. I suppose if I were on some sort of epic long-distance ride, I might use it for mountain biking, but honestly I can't see myself needing this much room for anything day-to-day. Maybe commuting, if you have a small laptop with its own sleeve. Hard to call too much space a negative feature, though, so five stars it is. I am very pleased with this pack so far, and would recommend it if you need a LOT of room for mountain biking.