Depends on the water depth more than the option between LEDS or T5.
Having a shallow frag tank and high powered Leds is a waste of money. After all its a frag tank. I cannot justify running 2 Radion Leds above my frag tank. I got good growth with normal old T5 tubes. First frag tank is only 70mm deep and 2 T5 tubes. Second frag tank is 250mm deep and also 2 T5 tubes. If I had SPS in there I would use my other T5 unit with 4 tubes.
What is the depth of your frag tank? And what type of corals do you want to frag?