Thanks to everyone for all the great advice!!
I found an interesting comparison chart
here.
While Fluorescent seems like a great idea for some, I don't really have space/temp issues. I guess I question how much more efficient the Fluorescent is when compared to the high output 400watt MH and from what I'm gathering, the MH promotes bushy growth with less stretch than other lights.
I believe I'll opt for another 400 watt ballast/hood and just use the 38,000 lums MH bulb I already have.