So my trusty Z55 has been doing me fine for the last 4-5 years. I really like how the frame transfers weight to the hipbelt. I also like how the hipbelt and shoulder strap material is really grippy. No major complaints, except that the airflow curvature behind my back places the pack away from my body, resulting in less efficiency.
But now I'm moving away from lightweight backpacking into UL backpacking. My Z55 weighs around 51 oz. I now use a SMD Lunar Duo tent, and am thinking of trading it this summer for a cuben fiber tarp. The rest of my gear has gone the same route. So what are my options for a COMFORTABLE, lightweight (around 20-32 oz) pack with a good internal frame? (I have low back issues, so good support is paramount). I'm not looking at frameless options. I also use an air pad, so using a foam pad as a frame is out of the question. So far, I've been looking at these:
GG Mariposa
SMD Starlight
ULA Ohm 2.0
I'm willing to consider mainstream as well as cottage industry manufacturers. Just looking for the most comfortable lightweight internal frame pack out there that can handle 20-25 lb loads with ease.

