Budget?
Are you trying to be energy conscience?
The only T5 I would buy or recommend is ATI.
If you got 1500 bucks, get this and have it all
http://www.reefgeek.com/lighting/le...le/36-2x75w-led-4x39w-t5-led-powermodule.html
a 36" 4 bulb ATI with bulbs is just under 500.00
Depending on what LED fixture you get you would most likely get 2 for full coverage and to be happy, you are looking at average 800 bucks.
If you deal with pure numbers figure out how long the 400.00 difference will get you in power bills.
LED's give shimmer, do you "need" or like that?
T5's IMO give better color.
The growth difference is prob. negligible.
I would say figure out your most important criteria and base your purchase off of that.
FYI I own a 6 bulb ATI sunpower. I have been very happy with it and did consider moving to LED but could not justify the cost/benefit ratio.