It's a meaningless statement.
LED is literally Light Emitting Diode, a semiconductor that produces light. An SMD LED is a subset of all LEDs that has a specific type of packaging.
The classic LED package, a small plastic bulb with pins on it, is not able to reach very high power because the heat it generates will fry it. One of the useful characteristics of surface-mount LEDs is that they can be mounted to a metal plate which draws heat away from the emitter, and thus they can sustain higher power (= more light output).
The seller might mean his SMD LED is brighter than some classic package LED he also sells, but the terminology is inaccurate. SirJMD is right that pretty much any high-powered LED flashlight today is already using a SMD component.
If you're looking at specific flashlight models, you'd be better off searching or asking on the forums here about them, if you're trying to understand what the differences are. There's more to it than just the specific emitters in them.
