Like twilliard stated it seems to be a very debated subject. I did read until my brain was tired! So I will tell you what I found and what I went with. I am assuming that your tank is 48" long with a divider. I did not go with a single long light because of the divider and I didnt want a shadow so that ruled out all the longer lights. Most of the Chinese lights are 16" and with a 90 degree lens two are the perfect spread over that length. So after looking at pictures, researching color temperature and light spectrum, looking for personal reviews, and trying to keep within a budget of $200, I Narrowed it down to 3 lights.
MarsAqua ebay lights are $165 for a pair. They are full spectrum and tons of people swear by them for the price. I did not go with these for two reasons. They have neutral white 7500k and warm white 3500k bulbs and they dont have any UV bulbs. Its been said that Neutral and warm white promotes algae growth and that UV supposedly promotes coral growth. So I decided to not go with these ones.
Chinese Blackbox LED Proof Group on Facebook has group buy lights. They have a direct contact with a manufacturer in China and have managed to get several models custom made for reefers. The basic light can be had for $99 each and a lot of people in the group swear by them. They have removed the neutral whites and changed the normal ebay LED's 10000k/12000k bulbs with 14000k bulbs. They also have a timer light for $133 each that has a slightly different spectrum. They removed the warm whites and added moon lights. I did not go with these because they use a 14000k bulb for the whites and IMO is too blue looking. Also no UV light. And lastly the bulbs are not zener protected meaning if one bulb goes out they all go out. They do have a very good support structure though if you have issues.
OceanRevive T247 timer S026 dimmer lights. Both lights have the same spectrum and spread but the T247 has a built in timer and the S026 does not. The downside is that they are a bit more pricey than the others. On sale right now for $136 for the S026 and $158 for the T247. When I first started researching, these lights where not on sale and where pretty far off from my budget so i did not consider them. However I noticed the sale so I started looking into them. Everyone has nothing but good to say about these lights. I found some pictures of the case opened up and they have nice heat sync's and fans which is nice because you dont have that guarantee from ebay lights. The pictures and videos I saw looked amazing for the intank pics. One had a MarsAqua next to one of these and the difference was crazy. In the end I went with these lights because first it is a U.S. company that sells and supports Chinese lights and two IMO the spectrum is a perfect 10000k/12000k white and 450/470 blue balance with 420 UV lights as well as some red and green for balance. At $136 x2 it was a little over budget but I gave myself some wiggle room. Then after looking again the difference for a pair was only $42 and I would probably spend that much on timers anyway so i ended up with the T247's.
Hope this helps!