I run the Mars Aqua 165W LED over my mixed reef (30" long). I installed it replacing a quad T5 and for over two months the system was shocked. No growth, just survival as mentioned before. I stuck with it and after the initial period I saw very good growth and coloration both on LPS and all my SPS were encrusting and growing. The only problem is that the majority of the LED pendants cannot cover well a 30" long tank so I just recently (a couple of weeks) I changed yet again to an Echotech Radion G2 with TIR 120 lens. Now this guy allows for much more controllability and it can cover pretty well my corners (>100 PAR). I am happy with this light but this doesn't mean that the Mars Aqua is not a good light. If I did it all over, I'd go for the 350W for my tank and that would have covered perfectly.
This is my own first hand experience, no hearsay on this. Also, the LED's had 0 degrading from day one to 1 year later. I measured PAR and spectrum with a seneye reef and nothing changed. In my opinion, it's not feasible to compare LED with either MH or T5 on maintenance and upkeep costs since LED's are pretty much the cost of the initial investment. The only difference lies in the spectrum/coverage/PAR etc. which we can argue about all day.
