I love T5 for veg. stage. I keep the light 4" above the plants and they grow bushy and tight without stretching. If you want bigger plants faster than I say go MH, if you don't mind the extra days then T5.
Definately go HID lighting for flower. I use a 400w Sun Systems ballast, Sun Systems 2 hood, and Hortilux eye HPS bulb. Around the ground I have 3 100w output CFL's that I put around the base of the plants and that helps the lower flowers get some light.
I will be trying 1000w HPS with 4 54w T5 6500k bulbs on each corner on the next round to see the difference with both spectrums. I've heard great things.
For clones and seedlings, definately go T5, awesome for clones. Maximum Yield magazine also had a study using LED lights for tomato cuttings and those worked well too. I feel the technology is too new still and it's more of a way for some folks to make some money in the cannibus industry...just my opinion. Using it as an additional light source is different(like a Kessil direct focus light) but as a main light I think there needs to be more research done. Like I said, just my opinion.
Ringo's Sour Tsunami sprouted in 3 days in 2" Grodan blocks with just RO water pH'd at 5.0. I use a 2 bulb 4' T8 for my fresh cuttings and seedlings then I bump them up to 2 T5's.
Good Luck!