Hi Ryan,
I have run with a semi framed Osprey pack in the (Japanese) Alps and up and down Mount Fuji. This was with (due to food and water) ≈17~19 pounds of total pack weight. It was a bit heavy but doable. You do get some more bounce on your hips, but when hiking of course you get to take some weight off of your shoulders.
I prefer now to go with a vest style pack though. When the vests carry well the weight doesn’t feel the same as just two shoulder straps carrying all the weight. I presume because when you get a good close fit the weight is more spread out over your torso. Not sure it makes sense the way I’m describing it but practically, my Montane Dragon 20 or UD Fastpack 20 feel, light compared to when I just hold it up in my hands. If within weight, I don’t think you will miss the frame. Or at least my guess is you might miss it less with a vest-pack than with a normal frameless back pack.
What I pref mostly of the vest packs is to just have the extra organisation up front. To have water up front, more on the side if you wish, all the other extra little organisation features – I vastly prefer a vest when actually on the move. Even hiking (if the weight is not more than ≈14/15 pounds). I’m now planning a trip to the Alps where I need to carry a bit more weight than the 15 pounds, so I will shift a bit over 2 pounds by carrying a litre of water and some small stuff (compass, phone, map, some food) in a separate running hip belt. If you are running up the weight ‘limit’, that is something you could look into as well.
You got already good list of example vest / packs that you could try there.
You could also take a look at these:
Montane Dragon 20 (reviews by Mike and me)
or their
Montane Via Dragon 20
Ian Corless was raving about the fit of a smaller version of this Inov8 pack (but for me the bottles get in the way of my arm swing):
Inov8 Race Elite 24
Not sure if this is the one you mention above but Salomon recently came out with the
Salomon S-Lab Peak 20
I tried it on and for me it fits really nice. But the vest pockets are less flexible I feel, would be very tight with standard PET or other hard bottles. And I also don’t know how I feel about a giant zipper going the whole length of the pack if I’m on a multi day run/trek in the Japanese Alps or whatever.
What I did like is the easy access (because of that same zipper) and the way you can compress the pack part down separate from the fit to your shoulders (it has same kind of zig zag little cordage as the ULA Ohm has). If your volume is often smaller I think this could be a great vest.
Overall I think the UD Fastpack 20/30 is a bit less refined and there are some points it could be improved on. But it does fit well, the usage is more flexible and it is more robust too (less stuff to worry about).
So in the end I prefer taking the UD Fastpack because I know it will last, I can use soft flasks or standard PET bottles, I can compress or expand because of the roll top, I have side pockets for more water bottles or food or microspikes storage, and I have a huge back mesh stow pocket for rain shell and whatever else you like to throw in there.
Hope you find what you need and have fun