Liked an ambidextrous safety for the left-handed crowd, but not a dealbreaker.
Liked to have had a more typical rear sight/front sight arrangement than the tangent-type.
After recently putting 5 magazines (100 Crosman .20gr 6mm BBs) down the pipe I have learned a few things. It does get dirty after a few magazines. The slide gets sluggish (ok, I watched a few vids on airsoft pistol maintenance, including the AirSoftGI one) and really need to better lightly lubricate it. I lube same points as a regular pistol - rails, barrel link, barrel hood (at muzzle) and slide stop.
There's a lot of talk about the lack of hop-up on the Hi-Power. Well, I can tell you, if you put an Allen key into the set-screw *towards the muzzle end* and loosen it, you'll be removing the barrel from the barrel block! the little rubber piece used for "hop-up" is inside that barrel block! Remove the barrel in this manner, and you can more easily clean it out with a rod and patches. (Ask me how I know . . .) As for the bottom hole towards the breech end (rear hole) no doings anything on my pistola; nothing there to turn/adjust.
Final Thoughts :
The Browning GP-35 Hi-Power 9mm Parabellum was the first handgun I ever shot. That was why I chose to buy it as my first AirSoft Gas Blowback pistol.
40-shots to a fill on propane/Spray Silicone @ 55-degrees.
Tri-angular front sight.
No written Manual came with the gun.
Propane smell in basement when shooting; needs adequate forced ventilation.