LED doesn't give you the grow. It gives you the shimmer and the "pop" or better adjustability than T5. You can simulate dawn/dust and midday with LED. T5 will give you the correct spectrum and true UV. And it's a proven technology to grow SPS. Most people I know do not get good growth with LED. But some people this forum reported good growth with their LEDs. Running T5 only is a bit boring looking, imo. The tank looks the same practically thorough the day...
LED + T5 is a great combo for growth/color and adjustability. This depends on what LED and T5 fixtures you are looking at of course. I am currently running ATI 8 bulbs + 2 Kessil 360W. Amazing shimmer and awesome color/growth for my SPS. I am very happy with the way things are right now. We'll see how it will turn out in the next 6 months/year.
Also, I have no issue with heat. I don't run fan or chiller and temp never goes over 79 degrees.
Keep in mind that water chemistry and other factors will determine your overal results.