the SSC/Cree stuff that came out around 100lm/w is darned good, It was one of those bizarre sudden *jumps* in tech that may or may not happen again. We may just see slow incremental increases in efficiency up to around 200lm/w over the next decade or so, or maybe there will be one more jump, either way, I don't know that it's *worth* taking the time and money to upgrade with each incremental step. I think it would be smarter to wait until the latest greatest is performing at least 50% better than what you currently have, which in my book only leaves room for maybe 2 more "upgrades" (one when things get to around 150lm/w and another when things get up over 200lm/w)..
Like many have said in the past, as efficiency improves, so will the current that they can be driven at (as less and less heat will need to be dissipated per watt of power going through the emitter)... I wonder, if they could really close the gap on the theoretical 241lm/w, maybe it will be possible to run these things at 20+W+ someday, pushing 4000+ lumens. If they get to 220lm/w, according to my math, a 20W emitter would make about the same heat as todays crees do at maximum drive, but deliver 4400 lumens at the emitter... pretty cool eh?
