I've had mine in for about 3 months at this point and the Gen2s made some big improvenmts over the originals IMO and not a single part from the Gen1 is present in the Gen2.

Improvements:
-detent in bale and mode switch
-true 1913 rail
-new beam pattern (see video)
-400 & 800 lumen output
-improved pad
-aluminum bezel
-aluminum threads
-improved material in the body

Full review here: