Differences between M&P9C 1.0 and 2.0 are as follows.
2.0:
has much more aggressive stippling,
Lighter trigger pull,
Crisper trigger break,
Shorter reset,
Reinforced steel rails for increased durability,
4 different sized backstraps vs 3 (S, M, Med.-L, L vs S, M, L),
I think there's one other thing that's different between the 2.0 and the 1.0. Just can't remember what it is right now.
I don't have any experience with the FN. I used to have two SIGs, still have the P229, but would sell the SIG before I sold one of my M&P 2.0s.
I'll just say that since I bought the S&W M&P9C 2.0 three years ago, I've used it in about a dozen defensive handgun courses, firing about 300-400 rounds per class, and have had exactly zero malfunctions. I put about 100-150 rounds through it per week, 40 weeks a year, and it always runs without a hitch, unless I do something dumb, like load a bad reload in it. Even then, my M&Ps are much more tolerant of my reloads than my Glock 19 Gen 4.
Another thing I really like is that the mags work like Glock mags, which is to say they always work flawlessly. That's the one thing I've always liked about Glocks, btw, is that their mags always work right out of the box. And the S&W mags are steel, so when you hit the mag release button they fall out of the gun like they were greased, the one thing Glock mags sometimes don't do.
I've bought two more M&P series 2.0 guns, and I wouldn't sell any of them. And I plan on buying a couple more. I think they are extremely good defensive firearms, and my M&Ps are the only guns in my safe that I'm seriously thinking about getting "spares" for. Well, and my S&W 1911 SC-E. Love that thing.