In reply to Sutty22:
AK is lighter and simpler, but generally very similar packs.
The Osprey has a more 'structured', comfortable feel. The straps, buckles etc also do a better job of 'staying put' on the Osprey, because it doesn't use the very thin/slick tapes of the Crux. Probably not a deal-breaker?
If you're likely to want to stuff the empty sack into another bag (eg to create one bag for the second on long routes), then the Crux may be a better bet as is more floppy/flexible.
All in my own limited experience.
Both very good packs.
Mark