I tried voice command maybe 1.5 years ago using the built in Vista voice recognition stuff. I found it was pretty responsive but it takes some time to actually say a word. I thought it was a lot easier for me to just hit a key instead. It just takes about .5 of a second to say something like "Stop" or "Heal Toon1" and I couldn't spam it!

So it might be good for less used commands like "rez toon1" or "buff party" but the combat stuff didn't work out for me personally.

It look really impressive showing it to my friends though.