I'm considering a full size 9mm. I can't really justify it, but still... Anyhow, I want something that's a bit more accurate than my 9C (longer barrel and sight radius, with the ability to mount the Mako sight mount). While I don't know that I can find exactly what I want, I'm considering:

Smith & Wesson M&P9L Pro Series C.O.R.E., with 5" barrel and slide cut for optics (an alternative to the Mako). Would possibly consider getting a .40, with a add-on 9mm barrel, which I'd get with compensator slots. 17 round magazines (just bought 2 for my 9C, so that'd give me extras), Striker Fire (Double Action, kinda).

Sig Sauer P226 Tactical Operations E26R-9-TACOPS, 9mm 4.4" barrel, double/single (10#/4.4#) trigger with extra short reset, comes with 4 20-round magazines. Also comes in .40, but don't know if barrels would interchange. More expensive, but easier to find than the C.O.R.E. or L.

In personal experience or opinions in comparing the pluses and minuses for the two? While the M&P seems to make the most sense, the Sig is certainly more of a "different gun" rather than a bigger version of my 9C.

I tried very hard to convince myself to buy the Sig Sauer, even had a heck of a good deal on it. Utterly reliable, very accurate.
I bought the M&P Pro for one final reason:ergonomics. It feels better, I can go faster, and it also is very reliable. I think it makes complete sense to get the gun that YOU shoot better, regardless of theoretical advantages.

You pays your money and you makes your choices.

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Science plus Art