I have both g19s in hand... WE G19 KSC G19 both are good looking guns, and have nice weight to them and metal slides. in the pictures attached, the WE is on the left, and KSC on the right. in short, niether one is an exact 1:1 with the RS Glock 19. Neither one fits in my G19 holsters, but they both fit in my G21 holster no problem (a touch loose, but I have a tension screw that will fix that). the reset on the WE is a little more positive than on the KSC, but the trigger feel is a little better on the KSC than the WE. I am not going to function test the WE as I am trading that to a friend for some 9mm ammo, but he has one already and he is quite fond of it. the magazines are not interchangeable, but I expected that. I like that the KSC has a cover plate to cover the loading port on the magazine so that it cant get filled up with dirt, etc.. during speed/combat reloads. the slides on both guns are exactly the same at 1 1/64" of an inch. I like the way WE did the extractor in their slide as its a separate piece of metal and it wiggles a bit and just looks more real. The KSC is molded into the slide and is fixed. the frame on the WE measures 1 1/8" wide The frame on the KSC measures 1 1/4" wide I opted for the KSC after purchasing the WE because it was said to be a more reliable system and a true 1:1 ratio. Im disappointed that its not a true 1:1 ratio, so im hoping that it is going to be more reliable in the long run and worth the extra money. also... the mag drops more freely from the KSC, if you press and hold the mag release on the WE the mag gets hung up, although if you just press and release it drops free. On the KSC, if you press and hold, or just press it drops free either way.