Full disclosure: I own 4 Osprey backpacks.
Personally, the two options I chose for the bike (Talon 22 and later a Manta 30) were chosen because they were geared towards cyclists in mind. For me specifically, commuting to school with no storage locker, the helmet clip is an extremely useful feature. Others might not need it at all, however. I would also venture a guess that people tend to look at companies like Osprey and Dueter because they specialize specifically in backpacks. The only reason I replaced the Talon with the Manta was for extra storage. The Talon was perfectly fine and didn't need replacing. I still do grocery runs with it and keep it on hand for other outdoor activities. That and Osprey does offer lifetime warranty on any and all products.
Short review of each: The Talon 22 was an awesome, lightweight, no frills bag perfect for small loads. My loads started to get fat and I desired more organization (pockets), so I got the "bloated" Manta 30. Both are awesome for their intended purposes.
Not trying to rag on Arc'teryx, or their great products. Just trying to explain the "sheen" of Osprey backpacks.