All luxeons need some sort of heatsink when operating near full power. Even the "1 Watt" kind get dang hot. (been there, burned my hand on that...) Luxeon III is about the price/brightness sweet spot right now at around $14 for average grade stars, provided you can handle that heat they generate. I run my Luxeon I's at about about 1/2 to 3/4 power in my projects to keep them and their regulators cool and near peak efficiency. I'm not totally pleased with the regulators I have for them so far.