When I downgraded to SL, I actually felt compelled to sit down and work again. I was smiling. I was productive. I was once again in my own little Mac-Heaven.*
My return to SL had an evil twist. I got tired of Lion's slow response, sluggishness, ugly interface and tendency to beachball on every application that has a database (PS 5, A3, iTunes, even iPhoto).
After building a SL install on a separate HD using the retail SL disc + the combo 10.6.8 + all updates my again MP developed fairly regular kernel panics after working with either Aperture 3 or PS 5 for. While SL was so much better to work with than Lion the kernel panics were too much to deal with. Reinstalling the latest combo didn't help.
I zapped the HD and installed SL from the grey MP install disc + the combo 10.6.8 + all updates. I also made sure that I was very selective in moving apps and data folders from Lion in case there were kernel issues created by the slight differences between the OSs. Same problem!
Now I'm back on Lion with its fugly iCal, Mail and Address Book. Fortunately the lack of Save As doesn't matter much because I use Office 2011. If I get ambitious maybe I'll rebuild the SL HD and stop at the MP's install disc 10.6.4 for awhile. I never had a kernel panic under 10.6.8, maybe it's that last 10.6 security update that did it.