its a good question, i actually use all three
-sunblaze 4' 4 tube 56w spectralux bulbs, 2 red, 2 blue- i use thise for my clones, uptill they're about 1 foot tall (after 1' the t5 lose alot of the penatrative power.
-So the 1' plants then go under 500w MH grow them another foot
then 400w hps to flower the girls
they stay nice and compact for the large size by the time i'm done
be carefull too the t5 will burn your plants if they grow upinto the bulbs