I'm thinking about partitioning my MBP (late 2008) to dual boot Snow Leopard and Lion. I found an article about running both OSes, and using the SL user account for both SL and Lion.
Should I trust it? Is it safe?
Unfortunately, at the moment Lion is still in pre-release phase, so I would not deem it to be safe nor trustworthy (until its officially released). Even Apple's own guidelines for installing pre-release operating systems to testers/developers say to install it on a non-critical hard drive in case there are problems.
If you want to test it out, I would install it on a completely separate hard drive. And without any critical data.