Got one, like it just fine. Great ergonomics, very accurate, good sights, low felt recoil, pretty compact for a double-stack .45ACP. It's also reliable as anything else that says SIGarms on it...haven't gotten it to fail yet.
Downsides: trigger might not be everybody's cuppa tea, takedown procedure is a bit involved, spare mags are too expensive at $50 a pop, and the safety is at the rear of the frame.
I fail to see how it would be any less durable than a P-series SIG. It's made out of the same alloy and steel, on the same machines, in the same factory as the P-series SIGs. The design certainly doesn't look fragile.
My $0.02 on the M2.