I love my halides. They look much better than other options, imo. They don't seem to be as bright tho. I've noticed this in both my reef and my planted tank. Not only do they not look as bright (per watt) but things don't grow as well under them (per watt). Most people in the know about these things would argue w/ me... The data says they should be about the same light output.
BUT, in my experience, when you use more wattage of halide they're awesome. I have 3x175 watt bulbs over 1/2 of a 200 gallon tank. The other half isn't lit (other than the light spreading over there from the 3 halides)
The lit half is heavily planted and doing great. I have 3 different bulbs in there. One 6500k and 2 different brand 10k's. I started w/ one 175, which replaced 2x90w power compacts. The plants died back a bit, and it just looked dim. I added the 2nd 175w halide after a few months, and then added the 3rd about 6 months ago. The aquarium got much better each time. It looks better now than it ever has.
Also, each time I added a bulb I lowered the photo period, and added more offset to when they go on or off. All 3 are only on for a few hours. The added intensity in those few hours had seriously doubled my plant growth.
the only thing about about lowering the photo period is less time you get to view your tank.. which is one of the drawbacks I was concerned about
Other then that I would probably choose the MH.. after all my research I think I am just going to go with the T5... whether its the right decision or not I just have to make one finally and get it over with