I've mentioned my experience with Lollipop performance earlier on the thread, but I'll recap. Individual apps are fast, but anything that switches tasks is very slow, and especially the task switcher. It looks like this is just an AOSP problem, as it affects basically everyone on grouper, tilapia, and several other devices as well. The app drawer and the task switcher are faster when you've used them recently.
I installed M-kernel for testing as well, but it didn't solve any of the performance problems that actually bother me. Metallice's CPU governor is very good, though.
If anyone has concrete suggestions for improving carcosa kernel on Lollipop, I'm glad to take them. Either here, or in the dev thread for the kernel.