You will get varying opinions here, it will be up to you to decide what is right for you but if sps is your primary goal then I would tell you to go MH hands down. You can choose wether or not you want to supplement with T5 or LED but In in my honest and fairly experienced opinion a good MH bulb/ballast combo will grow and keep you sps healthier than anything else out there with the least amount of fuss and configuration variables.
I started as an led guy using the best LED tech on the market and switched to MH and that wasnt even on my SPS tank. There may be someday in the future when LEDs have been figured out well enough to make them truly the new standard for coral (sps) growth but until that happens you couldn't pay me to go back.
You will get a lot of LED users that will say "I use led X and have great color and growth!". My answer to that is "compared to what?" There is no debate that LED can grow and color sps but in most cases not nearly to the extent of MH. Most the time when you hear that comment its coming from someone who (A) has never used a good MH bulb/ballast combo. (B) Dosnt have a lot of sps other than montis and birdnest. or (C) Isnt willing yet to admit that the thousands of dollars they spent on LEDs don't really work as well as they had hoped or haven't had them over their tank long term to really understand the consequences.
The next argument you will get is that LEDs cost less to run because they consume less power. Well yes and no. Maybe initially you will be able to run two led fixtures in place of two MH fixtures and yes it will consume less power. However, assuming you are lucky enough to even grow that sps into large colonies using said LED in the first place you will soon start to discover that the LED it too directional to provide enough lighting to the whole coral once shading starts to occur. At this point you will have to add at least two more of the same LED fixtures to match the complete coverage that two MHs will provide especially in the shaded areas and thereby you will now be consuming as much or maybe even more power as the MHs. Honestly when you do the math the expense is not that much more massive running MH over led anyway and what would you rather do, save $20-30 in electricity and have so so sps growth or spend an additional $20-30 in electricity and grow your corals to the point that you will easily make that money back in what you will have to frag?
The next thing, Heat issues with MH. Yes! that can be an issue, however plan for it, design your system for it and its not going to be an issue in this state. I run MH on all my tanks and none of them have ever once required a chiller. Not to mention in the winter you will regain some of the energy spent and heat expelled in not having to run a heater as much or at all.
In my opinion, all other things aside one of the biggest reasons to avoid led is that they are just too darn configurable and we don't have enough understanding about SPS coral needs. Most people will choose to configure their lighting to be the way they most want to view their corals and sadly that is not generally what the corals need or want and will eventually decline as a result. There is the other problem of too many variables and unknowns as to which ratio of color chanels will work for you, and what works for one person won't necessarily work for you. When things start to go wrong with the sps and you don't know why you will have that ever burning question in the back of your head asking if its something in the led spectrum you have chosen or not chosen or didn't even know was hurting or helping the situation. With a proven MH setup this is pretty much one concern you can toss right out the window.
All this said I am applying this logic based on the fact that you said "Mostly sps". If you were not going to do mostly sps then yes by all means look at LED as an option. However when it comes to SPS. there is a reason threads like this exist and are as long as they are.
Anyone Thinking of Dumping LEDS and going back to Halides
http://www.reefcentral.com/forums/showthread.php?t=2203067