I know X3 has VST3 integration, but I don't really know a lot about the differences between VST2 and 3.  I have a few Waves plugins...not sure what other EFX may have VST3 versions.  Is there any real advantage, in terms of sonic quality, CPU usage, latency, or something else I can't think of?  All I've read about is some workarounds that people needed to do to get their VST2s and 3s playing nice together...
 
Any feedback is welcome!  Thanks in advance.
 

As far as Waves goes there are significant advantages to using them over their VST2 versions, mainly because of various UI bugs that exist in the VST2 versions. The VST3 versions are most actively developed and supported by them as well.
As far as general differences - VST3 is a completely different spec that bears little resemblence to VST2.
There are a few advantages baked into the spec like silent audio CPU efficiency, sample accurate automation and various UI enhancements like hierarchical plugin and parameter categorization  etc. However it is up to the plugin vendor to implement these, so just having a VST3 plugin doesn't mean you will get those features.

Thanks for clearing that up, Noel. Very helpful.