Question about LR4 vs CS6
If I understand how you work now, then ACR should parallel a good portion of what LR4 does, but of course not everything since the ACR toolkit is smaller. I haven't upgraded my CS suite to V.6 so haven't seen whether the slider changes are identical. I'm sure the improved shadow, highlight and noise capabilities apply across platforms.
Confess I use PS sparingly since getting LR3, and LR4 is unquestionably better. I'll probably relent on CS6 because I also use AI and ID, and find Bridge pretty handy as well. I'm miffed they don't bundle Acrobat anymore.