I've had mine for a couple of weeks. Put 3-400 rounds through it of various brands, grain, etc. No issues whatsoever.
I bought it from Al Flaherty's and they had plenty of spare mags so i picked up two. Only issue with the mags is the cost at $62 each.
My friend was set on picking up a glock and i think he's changed his mind to a P320.
I've never fired the P09 so i can't compare it but i'm more than happy with my Sig. I'd buy it again and keep recommending it to everyone i know who shoots.