Same.
27" iMac, Late 2012 model
2.9 GHz Core i5
8Gb RAM
NVIDIA GeForce GTX 660M 512MB
Even with just SL running, I can't get more than 8 FPS and typing in unbearably slow using both the 32 bit and 64 bit versions of Firestorm. I'll type something and have to wait a few seconds before the characters start showing up...