I got one that was bleached (bad me! I didn't realize it at the time!) I wanted to feed it a lot, daily, but was cautioned by quite a few people not to, this could add additional stress. I also would not "force feed" the nem either. I would definately give it the opportunity to eat, but would not force it to.
I'm in the MH camp on this one. We've had one for about 16 months now, and got it when it was very close to death. We did everything we were supposed to and the biggest turn around was after we added the lighting. Now, since we didn't try any of the others (we went from PC) maybe they would have worked for us, but I don't know.
Another thing to consider, is that lights do go bad. Generally, they're good for about a year. Sometimes less sometimes more. Very soon we will require three MH bulbs, we're going to have to find a way to stagger the purchases so the sticker shock isn't so bad!
As someone else mentioned, but it's worth mentioning again, you're going to have some heat build up under your canopy from the new lighting, keep an eye on your temp! We had to cut ventilation holes in ours to keep it from over heating.
Good luck!