I liked the leds dont get me wrong. I loved the shimmer but i just didnt get the growth and color i wanted. Too be 100% honest, if i had room for a chiller i would have went back to metal halide. Im very happy with my ATI and im gonna stick with T5. Better results.
I would love to go the hybrid route but 1300 is a little much for lighting for me....and the hyperions which are beautiful dont come in the 24 inch size i need.
I have a dimmable ATI 6x39W that I am very happy with. I also run a 36" reefbright which is mounted to the light. For the price I think its hard to beat this. It is not as controllable as a fully integrated hybrid fixture. I happened to see a Pacific Sun t5 only fixture today and it was also really nice.
I would say go for the ATI T5 for now.
In a few years (3-4 yrs from now), it wont be late to try LED at that time.
for a 24x24 tank, i think you can get a way with a 6 bulbs (6x24w ati T5).
but the 8x24w will give you more options.
6x24 ATI is the superior lighting and more economical to purchase when you take in consideration that you need to hydras to match the coverage of this 1 T5 fixture.