sadly the issue is a lack of actual scientific study, we all are reliant a lot on user feedback, the issue is does that user have the knowledge to really be a viable source of education.
Here are my thoughts and I have been selling LED since it first came to real attention and that includes 4 of the leading brands.
To prove T5 or mH is better for colouration than LED is very very difficult, you can take your treasured T5 unit off your tank and put the highest end possible LED on the tank and watch the colours fade? Is that the fault of the LED? If you look deeper at the SPS stress reaction to change I think you will find the answer closer there. So you then have to slowly over time balance your new LED unit if indeed its capable in the first place to re capture the glory you had before.
My point above is if you change from T5 or MH to a well designed and research LED unit there will be a transition and this could be anywhere up to 6 months in my view. Also keep tweaking and playing with the intensity and output will only make matters worse. If you decide to buy LED expect a transition and it maybe a few months, if you buy the right fixture it will pay off, i am sure.
I believe the negative comes from the end user gets frustrated blames the lamp and goes back to a pre tuned MH or T5, low and behold in a few months things bounce back, most likely if the LED fixture (again if it had any worth) would have also seen the same corals come out of the stress pot and start to show their colours.
Another point, if you did not have much colour before, dont expect LED to suddenly be your miracle cure, some corals simply dont have the ability for many reasons to be blue green purple with pink spots, they are just brown. Did you buy it brown? how do you know its going to shine from here on? Whats your tank husbandry like (HUGE factor)
Quality, yes I sing from the high roof here because of what we distribute however I strongly believe based on seeing the immense amount of research that goes into these high end fixtures that you get what you pay for. I have no doubt in my own personal view you are not going to get much luck throwing a cheap fixture over your tank. Where is the development/research cost in that bargain price?
GHL took 2 years developing their reflector, they did not do that for kicks. Same goes for Ecotech with their in house TIR lenses.
GHL Mitras uses linear dimming to truly replicate the smooth dimming you get with T5, again this all costs money, but the results stand for themselves if you watch it in action. Both the above commonly are not found in lower priced fixtures, but its the bargain priced fixtures that carry the majority of the sales I would bet?
My theory is this - client buys "affordable" LED lamps ("well its got the same amount of LEDS or more as the more expensive one so...." but how does it deliver that light? spread? diffused? no hot spots? disco ball? Said client after 6 months does not get the results from his affordable LED and blames LED in general and goes back to T5 or MH.
My suggestion is and I speak as a hobbyist first (yes I do) if you are going to take the leap into LED look for the fixtures that the manufacturers have done their research and spent time and effort in development, look for long standing reviews, try and seek out the odd scientific review.
Dont rule out LED because it failed you, look outside the box, how long you gave it was the fixture truly a fixture that could replicate T5 and MH (I believe only two out there can), what was your tank like before the change and if it canned, how long did you give it to recover from the stress of the change.
I will quit my rambling here by concluding IF you are going to take the route of LED spend the money it will pay you back in the long run, but also expect a transitional stage.
I personally do not believe mixing LED with T5 is the answer either as the biggest driving force in the fixture is the T5 with LED providing effects such as tuned moonlight and shimmer. But thats my personal view.
