Just finished a 20 mile walk with this daysack and found it extremely comfortable as long as the chest strap is adjusted correctly. Space is a bit tight, but I believe that there are larger versions available out there (25L?). Thankfully, I found that there was no irritating "squeaking" noise from the straps that I have found on some other daysacks, particularly Berghaus.
I wouldn't read too much in to the "Laptop padded sleeve" or the shoulder strap on the pocket, both are useless for their intended uses!
I managed to squeeze a 1.5ltr camelbak into the pack, but it was a very tight squeeze height-wise; the bag has a stiff back which I like - nothing pokes me in the back, but it was exactly the same height as the camelbak so was a bit tight closing the zips. Worth noting that when the rucksack is full (and you're not using a hydration system), the hydration hole for the tube is stretched open allowing rainwater in - needs a waterproof liner.
Internal organiser is handy for smaller items etc. There's not much to the waist strap, but does its job.
The elastic compression is probably more of a gimic; doesn't do much. The side compression straps are more handy to stop items rattling around inside.
Overall, very comfortable, especially on the shoulders, although space is at a premium.