The whole 'weak around the trigger guard' thing is a crock, IMHO. I had never heard such a thing until some mk12 reviews started perpetuating the rumor of that corrected 'weakness.'
There is no real stress on that portion of the frame, and it is still built stouter than some other much more popular poly guns that do NOT have a dedicated internal receiver for the slide to ride on. The shock of recoil is on the trigger guard itself, or more specifically, the 'buffer' portion that is pulled down for disassembly. I have had my P1 apart tons of time and put a couple thousand rounds through it, and the takedown still engages just as firmly as the day I bought it.
While that limited anecdotal experience is not enough to convince any reasonable person, I think the amount of mk6's and mk7's that saw competition use with a LOT more rounds through them are a pretty good testament. I never heard any complaints from GP6 users about their frames or trigger guards having problems.
Oh yeah, and there's also the fantastic amount of testing that GP seems to do with their guns. 100,000 rounds through a prototype (i.e. probably less refined than the mk6) without failure? Seems pretty convincing. Select-fire models? Doesn't seem to have made any frames explode. I also like their test (it's on Youtube) where they do over 1000 rounds of +P+ without stopping for longer than it takes to swap pre-loaded mags.
I'm confident enough that my P1 sits at the ready as my go-to HD gun. And don't get me wrong, I'm not attacking anyone in particular, I just think that it's really wrong to represent these guns as being cheap because they're inferior. I'd put one up against a Glock or some other widely-perceived 'unkillable' pistol in a stress test any day of the week.