Yeah I'm still on VI too. No plans on moving to anything else besides Oracle VM 3.. if it ever make it out of the closet they are hiding it in.

The key with VI is to make sure that damn database is happy. It has to be defragged and cleaned quite frequently. I've never had any problems with it [Virtual Iron] other than database related ones....

As you mentioned the biggest change is IET/SCST. So I suggest you get some spare hardware and run the demo for a few weeks to months and make sure you don't have any problems.