when it's focused tight, it throws a good spot. On the other hand, it's really only impressive compared to stock stuff, current Inova XO from target has a better overall feel (and runtime, probably). I don't think it's quite the advertised 120-140 lumens.
A stock MagLED won't be too terribly bright either, but is still pretty sturdy, and the AA MagLEDs have surprisingly high quality reflectors. Still doesn't adjust to a wide beam all that well, but it's better than the Terralux (if maybe not as bright).
Oh - the standard Mag sized reflector won't fit a Terralux, would have to be a textured reflector made specifically for the Terralux dropin.