I'm a pretty experienced MODO user and have been testing vray for MODO beta. On some current arch viz work the MODO renderer (which is great for many things) just could not cut it for my interiors. The Vray beta is not solid enough to use in production, and I hate how much you have to tweak it. I transitioned the entire job to Max and corona and it's been rendering fast and I'm quite happy. It's convinced me to hold off purchasing vray for MODO when its released... hoping for a corona/MODO version.
The Corona maya alpha and the hope for a MODO version would be great. MODO is an up and coming star free of lots of legacy issues and it's user base is exploding.