Things I liked: The frame is solid and feels accurately sized in my hand. The functionality of the GBB is identical to the real one, from take-down to mag change/decocking/slide stop.
Things I would have changed: Although it looks identical in size to my real 226, the GBB is tight in my SERPA holster, whereas the RS has some play. It's not so tight as to hinder the draw, but does require that you push your thumb against the slide as you reholster to prevent the slide from being pushed back and out of battery. The grips on the GBB are not as high quality as the metal as well, feeling cheaper in your hand. If you shoot with gloves, you probably will not notice this.
What others should know: I have had some trouble getting this gun to run reliably. From what I have read, some of the plastic internals are prone to quick cooldown. I have experienced mag venting at inopportune times. This may be alleviated by using different gas, but I am still troubleshooting. I have also ordered several metal internal parts, but have not received them yet. The TM version has a similar price point and supposedly better internals at the cost of a non-metal frame. Worth a look, perhaps.