If I am not mistaken are the frames, including the trigger still made in germany? and just the slide is US made and assembled on this side of the ocean? If thats the case the tirggers should be the same. You can tell the diffence any european made pistol is a much finer metal than the corse north american steel.
I had a sig 226 fully germany made was awesome gun unfortunatly I have very small hands and was not the best fit for me am looking possibly at a 229 but for now got an M&P, fits the hand well shoots well and i get more practice with what I carry.
I'm pretty sure the trigger mech parts are made in the US, at least the trigger itself, but no the frame is made in Germany on most of them (although there are US-made frames about, the serial numbers begin with "UU"). However there is more to it than just that, there is the fitting of the parts together. The German ones are better fitted, for certain.
I tried a P229 some years ago in the UK that had German proofmarks on it, it was definitely a better put together gun than the US ones (I've owned three), but the slide was a US slide, just like the US guns.
The P226ST I bought here had an abysmal trigger pull on it, but the frame was made in Germany.
I've noticed this in the past, at the club I was a member of in the UK, we had a guy who imported a Glock 21 from the US, and another guy who had a Glock 21 he'd bought in the UK, the one with the Austrian proofmarks on was fit together better, no question about it. There was more slop in the American one.
Maybe the springs have something to do with it too, the main springs I think are made in the country where the gun is assembled, that has an impact on the trigger pull. But when I took my P226ST apart the main problem was definitely lousy sear engagement. Yeah it worked but it was awful. I replaced the sear and hammer with ones out of a German gun and hey presto, trigger pull improved significantly. Put a Wolff mainspring in it and it's fantastic now. Never had a misfire.
Reminds me of the Tanfoglio pistols, everyone thought they had hideous trigger pulls. Yeah, if you bought one put together at the factory in Italy, but if you bought a Springfield Armory P9 that had been assembled in the US, it was the same gun but the trigger pull was far better.
It's down to the skill of the people assembling them.