Pros: Comfort. This is the most comfortable rucksack I’ve ever tried. The harness transfers weight to the hips perfectly and the back system is brilliantly breathable. You can get lighter rucksacks- but then you could carry all your gear in plastic bags if you really wanted to save weight- in my opinion (and experience) it is worth paying a bit of a weight penalty to not end every day with aching shoulders and a hunched over posture.
I am not normally a fan of floating lids- they tend to fall forward when the bag empties letting rain into the top of the bag. This lid doesn’t do that and anyway the flap under the lid protects the main compartment anyway. This flap has clever little buckles so when the main lid is removed it can be used as a lid itself. To me this makes the lid kind of redundant so I would normally just remove it: you lose a pocket and can no longer overstuff the bag, but you have plenty of pockets anyway, and if you need more space in a 65L rucksack you are probably carrying way too much! I just remove the raincover as I never use one. Ditto the sleeping mat straps.
I also don’t normally use separate top and bottom compartments but the divider is so lightweight that it’s not an issue and I do find it useful to be able to get into the bottom of the bag.
The stow and go pole holder is great. The tool holders are also a very clever design.
The mesh pocket on the front is great for wet gear and the bottle pockets are actually useful- unlike other bags you can actually get a bottle in and out with the pack on your back. I put my jacket in the back mesh compartment and my trousers in one of the mesh side pockets.
The adjustable sizing works well- you can’t adjust the back length while it is on your back so it might take a few goes to get it right but unlike some other systems it stays in place once locked in so you should only have to adjust it once.
Not having side pockets would not be a deal breaker but it is quite nice to have somewhere separate for my stove, and somewhere to put small items, especially with the lid removed. Filling the side pockets decreases the space in the main compartment but 65L is plenty.
The Cons (some of them not really cons, just things to bear in mind).
The hipbelt pockets should have been made of stretch like the montane bags- you can fit a small pair of binoculars or GPS (I have a Garmin GPSMap62S) in, but it’s a fight to get the zip closed and impossible one-handed.
The mesh on the bag means that I would not check this bag in to a flight without putting it into a duffel/ Airporter, or at least getting it wrapped in plastic.