Just some quick results from the first fire of the S&W M&P45 after (almost) all the Apex Tactical parts were installed, and all proper magical procedures invoked. I also shot my Gen1 Glock 21 as a control, and because I have new plans for it in the near future.
Both handguns started out box-stock at about the same price. Both performed adequately, and rpovide good value for the money. I spent $250 on a Bar-Sto target barrel for the Glock, because the stock barrel was rather notorious for its poorly-supported chamber. It also shrunk group size by about 25%, nothing to sneeze at.
The money spent on the S&W, plus my own blood, sweat, and Nanoloube, changed it from a Chevy Cruze to a Corvette Z01. The Glock went from a Ford Escape to an Escape with a bigger engine. The trigger pull on the S&W went from a sane, sensible, dull, gritty 7 pounds to high-performance 4 pounds, 14 ounces (so far), with about four pounds of long-but-near-weightless takeup, and a barely-detectable sear letoff of under one pound.
YMMV, but for me, these Apex-equipped M&Ps are like building an F-16 from a parts kit. If I hadn't done all the work myself, I'd probably be afraid of the weapon if someone just handed it to me. But three-of-three successful projects have me so "sold" on the process that I'm fighting the temptation to buy an utterly redundant M&P compact or 9mm just to do it all over again.
And to think this all started from buying a plain vanilla M&P .357SiG that had sat on a shelf for four years before I bought it on a whim. So now I know how to build a "pet" AR15 and a "pet" S&W M&P that perform insanely well, with several successful examples of both already completed.