I'm 6'4 and its spot on for me size wise. I know a mountain guide who is 5'10 and loves it too.
EDIT: One more pearl of pseudo wisdom. While a few external pockets can be handy, generally I find that having fewer pockets and bigger main compartment to be much more practical in use.
If you're curious as to what I use, I'm a big MIllet fan (unrelated to UK highstreet brand Millets).
This my current favourite:
https://www.millet-mountain.com/ubic-40-backpack-hiking-khaki.html
I'm 6'4 and its spot on for me size wise. I know a mountain guide who is 5'10 and loves it too.
EDIT: One more pearl of pseudo wisdom. While a few external pockets can be handy, generally I find that having fewer pockets and bigger main compartment to be much more practical in use.