If the goal is to have the best of the best, then by all means go T5, but I stand my ground and say that the hydro and grow industries have hyped it up so bad that the prices are ridiculous. Look at the differences in efficiency from the T12 compared to the 5 and 8, there isn't much difference. In the color scale it's better as well, but not by a margin that justifies it's exaggerated costs. That is all I was saying.
I'm happy with my T8's
My plants veg just fine for the first 2 weeks, then they go under LEDs anyways.