I downloaded the latest nightly build (v2005-09-04) and did a rescan with the 
new various artists functionality enabled. This was the main reason I wanted 
the nightly build, as I have a lot of various artists CDs in my collection. So 
far, it looks like it works fairly well, with one exception.

Some time ago, I went through my collection and put in TSOP tags on a number 
of my MP3s. This worked well, and got artists sorted into a good order (e.g., 
Jeff Beck showed up in the B's). However, with this latest build, I noticed 
that any artist that have tracks in both a "normal" CD and a "various artist" 
CD is now showing up in the "wrong" place (e.g., Jeff Beck now shows up in the 
J's). From what I could see, this does not affect artists that only have 
tracks in "normal" CDs (CDs with only that artist).