I'm having a problem with the beta, they've come back to me about it but no resolution as yet.
Problem occurs with large AVI T2 files, Vegas will not import them.
AVI T1 files Vegas doesn't like the audio and builds a proxy. This is very odd as both files data streams would be identical as they're from ADVC-300. I've had the same kind of issue with AVI files from ULead MSP 7 as I'm having with AVI T1 files from DV Rack.