Ive use the Virtuous Xoom and i'm currently on the Virtuous Thrive. Both are really great ROMs.
But i'm liking the Thrive more.The Xoom ROM was better for accessing the internal and external memory through the computer and the Thrive only lets me access the internal memory through the computer.
I think for me the Thrive is more stable. They both are stable but I had a few lock ups with the Xoom.
I am currently on Lightspeed 1.0 ROM. I had no problems flashing it. I wanted a ROM that was similar to stock/OTA HC 3.1 but already rooted. Lightspeed fit the bill. I even got Netflix to work with the ASUS Transformer patch.