Well, yesterday, I decided I had had enough of Lion; not really Apples Fault, but, between the lack of drivers for some peripherals,(HP Printers/Scanners), and other reasons already covered here, I decided to go back to my perfect SL Time Machine Backup; I inserted the Snow Leopard Disk, booted from it, and restored a back up from a few weeks ago...Worked perfectly, except the "On My Computer" emails did NOT show up in SL mail; I tried restoring 3 different email back ups I had, but I could not get the "On My Mac" folders to show up. I keep tons of important business emails there, so, I decided I had to go back to Lion..
I re-inserted my SL disc, booted to it, and, once again restored, via time machine, but this time from SL to Lion...
Everything worked perfectly, and my email was back where I expected it!
point of the story is, you can easily go back and forth from Lion to SL, if you have enough backups on your Time Machine drive; you just might not get everything back the way you expect it in Snow Leopard if you do!
I re-inserted my SL disc, booted to it, and, once again restored, via time machine, but this time from SL to Lion...
Everything worked perfectly, and my email was back where I expected it!
point of the story is, you can easily go back and forth from Lion to SL, if you have enough backups on your Time Machine drive; you just might not get everything back the way you expect it in Snow Leopard if you do!