Got some hands on time with the 2 the other day at their SF event.
I thought the Rosewood back looked the best, but the kevlar back felt the best. The kevlar was smooth, yet soft and grippy. Similar to the black Nexus 5, but better. The sandstone back didn't feel quite the same as the one on the OnePlus One to me. I didn't like it as much.
The phone felt really premium in hand and I really liked the metal sides.
It also felt smaller than I was expecting, but maybe that's because I've been using a Nexus 6 recently.
Performance was smooth and snappy. Definitely smoother than the OnePlus One.
The screen was plenty sharp, colors seemed fairly accurate, white balance was on the cooler side, which I like, and it got really bright. It might have seemed a little washed out, and I'm not sure about black levels, but I would need more time to know for sure (only had about 5 minutes).
Not so sure about the capacitive buttons. I had to think about which one to press because they aren't labeled / both use the same symbol. But I would probably get used to that.
I took a couple shots with the camera and they seemed good, but the camera app is super basic and quite lacking. No auto HDR, no 1080p60 video, no manual settings AT ALL. HDR shots seemed a little slow to process. Slower than the S6, G4, and even Nexus 6.
I like Oxygen OS. Seems a little more simple and polished than Cyanogen OS, and the dark theme and accent color setting are cool.
Will probably wait for the new Nexus phones before buying. There will be a lot to choose from this Fall. OP2, Moto X Pure, Nexus 5 2015, Nexus 6 2015, Note 5, and possibly others. Going to be a tough choice.