The best testers are corals themselves
All the theory and testing aside, the bottom line is they work well. Some of the nicest captive reefs in the world are being kept under T5 lighting. If you know of an SPS tank being kept under PC lighting I would like to see it, so far I have not been able to find one. Before I switched to T5s I did a lot of looking around, and could find very few people who acually used them who didn't like them.
Rob