Lighting is a very personal thing, we all have different tastes and color preferences. Some like more blue, other more white or even the purple of actinics.
Myself, I love the shimmer effect of Metal Halides and the explosive growth they provide. I also still use T-12 VHO URI (now UVL) Super Actinics for supplementation but do not run them much since switching to a higher k MH bulb than the 10k I used to use. I have yet to jump on the T5 bandwagon even though they have come a long way in the last few years as far as coloration and variety.
In order to pick lighting you need to look at as many different combinations and systems as possible before making a choice. If shimmer is not a big deal T5 with good individual reflectors may be a good fit for you. If shimmer and fast growth are more what you are looking for then 2x 150, 175 or 250w MH with or without actinic supplementation would be my choice. MH bulbs in the 10k range need supplementation while those starting at 12k up to 20k may not depending on the particular bulb. I am using Reeflux 12k and they need only a slight amount of actinic so I rarely run the 2x140w VHO's and save on electricity unless I want to impress someone who has not seen the POP the VHO actinics provide. The new Coralvue 14k is supposed to be an awesome bulb as far as color, growth and PAR or power so will be my next choice.
T5 may be in my future but I'm not there yet, I love the shimmer the point source light of MH provides and there are too many bulbs I have not tried yet and may like.

Whatever you buy, you will need two MH for good coverage and individual reflectors for T5 is you go that route.