I have checked that set up out several times, I don't even have to click on the link. I think that it is pretty nice, but you just want to make sure that you are ready to deal with a little more heat than if you were just deeling with florescents because the 150 HPS will put off a little more heat than the average CFL set up, but I think that it may be worth it if you can deal with it.
What style do you want to grow? I think that the light would work best with SOG, SCROG or LSTing.
The 4 ft one is nice to with 50000 lumens it seems like it would rock in a SOG set up if you did it right and could control the heat as well.
Adieu