Do it, you won't be disappointed, there of course is the small chance you brick, but the expirence is AWESOME!!!! I have been running the Sense 3.0 Preview for a few days now, and it is AMAZING!!!
Hey I just flashed to gingervitis 1.0 with the MR2 and love it, are you using the weather wallpaper? Pretty sweet.
I only have 2 problems, 1 is the haptic feedback on the keyboard won't go away, and 2 there is a sound EVERY time I unlock that I can't get rid of.