Current Regulation vs. PWM, what is the difference?

I see folks on this forum talking about the non budget lights using current regulation and the budget lights using PWM. What is this, what is the difference, which is better?

PWM is explained in our Wiki ... think like a very fast strobe...

Thanks for the help, that answers my question :)

It's more simple/cheaper circuit w/ modern microcontrollers. You get worse battery life because emitters are less efficient at high current (esp at the DD 4V drive that cheap lights use.