Jhull9200, there are several questions regarding leds that if you answer, you can get some real help.
1) Do you want 1 long fixture or are 2 shorter fixtures or 3 pendant fixtures OK with you?
2) Do you want hanging fixtures or fixtures with legs? And do you have a canopy over the tank?
3) Do you have a budget in mind?
4) There are basic Chinese black boxes that work very well and come in several sizes. ($100ea. to $200ea.)
5) There are a few that have built-in timers to turn the 2 different channels (white & blue) on and off. ($140ea. to $200ea.)
6) Do you want sunrise/midday/sunset/moonlight control? These come in several sizes and are better looking than the Chinese black boxes (but good looks doesn't help coral grow). ($150 to $350)
7) Do you want more than 2 channel color control (like 6 or 8 channels)? These have sunrise/sunset ability as well. ($250 to $900)
8) Is a remote control good enough to set the lights or do you want WiFi or a computer to help set the lights? ($300+ to $900)
If I were in your position and just getting started, I'd go basic Chinese black box and keep it simple. They can grow any kind of coral in your tank, even at 30" deep. With a 6' long tank, 3 Mars Aqua or a couple of other brand fixtures at $100 to $125 each or 2 fixtures that are 32" long at about $175 each. Don't hold me to the price quotes, but I'm in the ballpark.
Once you know better what you are going to keep and you figure out what features you really want, then buy what you want and sell the used ones (or hang on to them as backups).
BTW, none of the features discussed above grow coral any better than the inexpensive Chinese black boxes with 3 watt leds. They give you the ability to make the tank look better for your pleasure, but do very, VERY little more for the coral.
And there is no best fixture. People who tell you their's is the best are really telling you their's is the best for them. But it could be way off the mark for you. You need to buy what is best for you.
I like the control of sunrise/sunset because I'm home a lot and I like to watch the tank change as the day progresses. And I like having 6 channels of color control so I can fine tune the look in my tank. And a simple remote is all I need to set my lights, I don't care about WiFi or computer help setting them. I also have a fairly good budget so I could afford $900 for 2 fixtures ($600 for the big one and $300 for the small one... when they were on sale). Did I need these to grow healthy coral? Heck no. I used Chinese black boxes over my previous tanks that cost way less and they grew coral just as good as my new, more expensive ones. And mine are FAR from the most expensive. You'd need at least 2 and probably 3 Eco Tech Radions at $900 each (that's right... $2700 total) and they won't grow coral any better either!
This is what mine look like: