Feature:
My favorite tools are the 3D track motion, audio and video track envelopes for volume, composite and fade to color. The transitions are top-notch and you can download other transitions and effects. You can easily composite backgrounds and overlay video in many layers.

Quality:
Vegas has always been rock-solid and crash free in Windows.

Value:
Very competitive price as it is in the same league with Premiere Pro, plus it includes the DVD authoring, but I do wish it were cheaper!

Desirability:
It is simply the best!

Sound:
Vegas is THE BEST NLE editor if sound is important to you. Vegas began as a multi-track audio editing platform! It is easily equal to or better than Adobe Premiere Pro, and blows away lesser software with it's flexibility and power.

Ease of Use:
Vegas handles many different types of audio / video formats from MP3 and WAV to motion J-PEG, quicktime, Windows Media, and even DVD video tracks.

Support:
Not sure on this one but I'd say it is at least above average.

Overall:
I've used Vegas from version 4 through Version 7 and it just keeps getting better!