For those that didn't try the beta, I'm been using two new FX filters quite a bit. The ones called Color Corrector and Color Corrector-Secondary. Vastly superior to using the older method of adjusting levels, HSL, color balance in combination. Reason enough to upgrade in my opinion.
Being that unabashed knob twister I am, I had to try reworking some of my older videos that I had already painstakenly "fixed" with version #3 of Vegas. Not only have I made them better across the board, the process is much easier and faster in version four.
And another new feature, Video Scopes is super. Using just these new features you have very tight control over how your videos look, you even get to have a before and after view in real time on your external monitor at the click of a button. Way kewl!