I have to admit that I have been wondering about how people planned to power these things, and more importantly how they were going to handle the heat. In my 6P, a 3.7V incan assembly running at less than 2.5A generates a considerable amount of heat even if I've got my hand placed just-so to sink it as well as possible. Those people planning to run units with currents higher than 3A are going to find that they're holding a small heater after a few minutes, not to mention suffer with runtimes less than an hour. If that's what you're expecting and you're OK with that, well that's up to you, but personally I think 3A is probably the happy medium. I chose a little less than that so that I'll still get an hour runtime even as my 18650s age and reduce in capacity, and the flux will still be considerable... Kudos to Matt for providing a product where this degree of choice is available.