I already own the 44L one. I used it for travelling and some hikes. I really love it !
It is really comfortable and you could spend a whole day carrying it without any problems. The padding on the back and the straps is really thick and lets your back breath pretty easily. The hip belt is also really comfortable!
There are 3 main compartments: top one for quick access, main one which contains a laptop sleeve/Water bladder pouch and a back one for small items. There are also water bottle pockets, side pouches and a stuff pouch on the back.
You can remove the hipbelt and the internal dorsal bar if you want to.
One of the main selling points for travellers is the U-Shaped zipper which makes it easy to grab stuff at the bottom of your pack.
The fabric is pretty sturdy and water-proof(ish), don't stick it in the river expecting your stuff to stay dry but it can handle some rain.
I live in europe and use it as a carry on. It's supposed to be a little bigger than regular airlines recommendations but i used it with copanies such as easyjet and never got any problems.
The only things i would add are:
- A pocket to the hip belt
- Lockable zippers