The FNP: A great SA trigger, changeable backstrap, tank-like reliability (must say I haven't run mine HARD, but I don't clean it), and a nice $350 price two years ago. But yes, very limited accessories due to low adoption.
Here is a great write-up on it from Stephen A Camp.
Still waiting on a Raven holster that's on order, and Atomic Dog doesn't make holsters for it. Night sights are limited too - definitely no HD Hackathorns.
Those things are making me consider a Glock 19, M&P9/9c or P30.