Having held a P80, I like it’s aggressive texture more, like the actual hand feel of the Dagger WAY more though. Grip shape.
I have however put together an 80% Arms GST9. The Gen 1. It sucked. First one had a jig issue and the locking block had a bad burr on it (easily fixed by me but they also sent an entirely new frame, jig, and locking block. I later repaired the old one by jb welding the holes I made back up, redoing with the correct straight jig.) I had also waited over a year to get my Od version, I called and they said it would be another year, I asked them to just send me a FDE one instead.
I then proceeded to at the time, follow the online con artists hype of recommending Rockslide USA. I have spent more on that gun that I did on a base Dagger, but only one of them works properly. The Rockslide wasn’t heat treated right and the connector was actually wearing a groove into the cam in the slide, making the connector effectively get bent inward more as the cam went farther away and prevented resetting properly, and the trigger pull would get heavier and heavier with each shot until it would refuse to fire at all.
Got another slide from them after arguing that their lifetime warranty should not require me to pay for shipping to them, since THEY screwed up. They sent another. Underside of slide where striker sat was bent DOWNWARD into the trigger group area. I had to file and lightly hammer that bit flat so it wouldn’t catch, then clean the inside so the striker sleeve wouldn’t get gouged. Same issue with the connector cam groove wearing through the slide. The slide catch notches also wore really fast too.
Argued again that their slide was junk and I would not pay for return shipping for a product they messed up twice. They never agreed, and I honestly threw the slide in the trash before they got back to me with their answer anyway. Threw the barrel out too. It survived a few hundred but at that point I didn’t trust anything they made except the optic cover plate.
The frame itself also sucked. Didn’t fit together tightly like it should, with big, easily felt gaps between the grip piece that you attach and the frame itself. Didn’t take modified trigger shoes very well, and the worst part is the locking block/pins/slide stop interaction. It’s a single trigger pin, no other pin in the locking block, so nothing for the slide stop spring to rest on properly. The locking block shape and it being farther away meant that during firing your slide stop spring could slip under the locking block, making your gun lock open every shot.
Now completing the frame, bad batch of internal parts and jig issue excused, was really easy and fun to work on.
I have heard and seen actual P80’s working way better, so I’d stick with those for a DIY build. Or the Strike Industries frame, from what I hear they are similar in feel and style to the premade SCT-9 frame, which I do want but I already love the Dagger too much.
I have since retired the two GST frames and used all the stuff inside as spare parts.