L.E.D. vs HALIDE/T5/VHO

[Ron99]

The difference between LEDs and Halides and T5s etc. is that LEDs spectrum does not shift as they degrade. They simply lose output. With MH and florescent lights the spectrum shifts to undesirable wavelengths which compounds the loss of PAR. LEDs should last longer because they will only lose some output but not shift in spectrum. So 6+ years is a reasonable estimate for LEDs.

The added difficulty of changing LEDs will only be an issue if their lifespan is far less than what is estimated and I guess that's the crux of the argument. You either think they will last or you believe they won't. I suppose only time will tell.