Hi - I have had an Aarn pack for about 4 years now - very happy with it. The model I have is called 'Featherlite Freedom' (55 Litre plus another 10 litres in the front pockets. This capacity suits me for almost anything, trip-wise.
I *nearly* fit everything in for a 10 day trip through The Reserve (CM-LSC NP) last year, but couldn't *quite* manage it. Took a larger Osprey instead - and felt the pain from that.....
First time I tried one on (aarn pack), it was a hot day in the non-airconditioned outdoors shop. As the sales guy strapped me in to the pack, (buckles, strapping, adjusters) I rebelled - "nuh, no way, too fiddly, too sweaty, don't think so !" - and left without purchasing.
A crook back one spring led me back to retry the pack - this time with a proper fitting in better conditions, and a bit more of understanding of what was going on, design & function-wise. A bit of further tuning out in the field and - Ha !! load-carrying nirvana was achieved !
The key to the thing to me, is the forward/backward distribution of weight - you really want to get the closest you can to "balance" between front & back. You will probably never get it really balanced (or even that close!) , but the closer you get, the more comfort you get as your back & neck muscles have less work to do, and your posture becomes more upright.
If you stop and think about distributing weight over your shoulders, the front/rear thing makes sense in terms of load carrying.
It IS more 'fiddly' to take on and off than a Macpac or a One Planet or whatever (at least on my old model - I would think on all models). So I guess that's either going to drive you mental, or you get used to it...
The front pockets - which everyone thinks will be "the worst feature" - are surprisingly easy to get used to - in my experience anyway.
I (for one) would be really interested, Devon Annie, on how the pack goes for you .
No barrow to push - just interested.
Cheers all