I had a dabble with the demo last night.
It is good fun speaking your orders, but I did have trouble figuring out which unit was which or where the full battlefield view was. Saying that I only did the first part of the mission and the units response was very good.
I'm not a fan of RTS as I am a bit slow to respond to whats going on, but with this voice command gimmick I could be tempted to play this one.