I've been working my way through various flat strings to see what I like best. In addition to the oft-discussed bright vs thumpy scale or string stiffness, I'm also noticing that the surface feel varies quite a bit as well. Generally this is only mentioned in passing, though it's well-known that on the roundwound side nickel strings feel softer than stainless most of the time. I guess I'm sorting flats into three categories: Sticky, grippy, or smooth. Most flats I think are trying to be smooth. I've seen comments that some of the sticky strings will become smooth as they break in. Grippy, the string is smooth, but it catches at you if you are pressing harder.
Anyway, feel free to add your evaluations, or disagree with one of mine.

Here's what I've tried so far...
Smooth:
- Fender 9050
- D'Addario Chromes
- GHS Precision
- (honorable mention) D'Addario tapewound
Sticky:
- D'Addario Half Rounds
Grippy:
- Rotosound 77 Jazz
- GHS Pressurewound (on the border of being smooth though)
Thoughts?
Thanks in Advance!