Time makes the difference ...

05/20/2015:
After almost three years of using this backpack, I find that the system with a single shoulder strap is not a good idea.
When you made long walk, it ended up hurting you in the shoulder, as the full weight of DSLR + two goals + 2 + flash + additional batteries charge leads ... eventually weigh really heavy in the evening.

So I recommend you rather preferred a backpack with two straps. After 17 days of marches, this is destructive to the shoulder.

I was looking for a backpack for my new Sony Alpha 57 DSLR and my Tamron 18-270mm.

Several bag doc tried me, including the famous Lowepro, which are really the top of the basket (but also for their price)
Of shots I very happy with this bag Montona because it offers a very useful storage space:
-opening side to access the camera
-at above photo compartment, large closet space there, charger, battery, multi-card reader ... or just a bit of water, food
-another smaller for storage compartment (in part) of what I mentioned above
-a non adjustements strap to carry around a tripod
Transport -sangle the backpack to a branch (see photo 3 product) rather pleasant
(I will detail this part more after my holiday to give you an answer on 3semaines of use)

And pletit more important in wet weather, a house fully enveloping protective backpack !!
account should think against the waterproofed before leaving !!

For now I can only recommend for:
-its various handy compartments
-its Tripod Mount
-its protective cover against rain
-and its price!