I have on my msi workstation laptop, it has 3x 512gb msata ssd, and 1tb evo ssd. I have windows 7 on 1 msata, windows 8.1/10 (dual boot split partition) on 1 msata, and yosemite on my 3rd msata. Yosemite is less than perfect with drivers but runs overall pleasantly, 1080p screen, keyboard, mouse and everything works great. My quaddro K5100m is unrecognized but I use windows 7 for all my heavy lifting anyways.
I tried installing mavericks as a vm inside my windows 7, that didn't go well at all. So that's why its on its own drive now. I'm pretty sure the format of drive had to deal with some/most of the issues.
I can say that no, battery life isn't noticeably better. about 4 hours on windows, about 4 hours on Yosemite.
I have no 'real' use/need for Yosemite, but I did it because I could, and possibly bragging rights idk.