Funny, I've been debating the same thing recently. I love 1911's and Sigs but was leaning towards the P210A because I already have a couple of 1911's (in 45ACP) but the Sig would be completely different then anything else I already have. I got to finger fuck both a P210A Standard and Target at the LGS and really liked the Target model.
That said, the capacity of both suck, especially the 210. In this day and age there is no reason to get stuck with 10 or less rounds on a full size 9mm. We may get stuck with some kind capacity restriction soon enough but why limit ourselves now? That's why I started looking at other options...
Obviously you have the various 2011 type pistols. Nice but stupid expensive (and the mags are stupid expensive too). Dan Wesson's DWX could be the ticket but I'm loosing hope in that thing ever coming out and even if/when it does, I don't guinea pig or beta test brand new designs. I'll leave that to others so even if it came out tomorrow, I'd wait a while and see how it works out for others before spending any of my money on one.
So then I started thinking, what's so special about the DWX? Its basically a CZ Shadow 2 with a 1911 trigger, slide and controls. Well what's wrong with the standard Shadow 2? Short answer is... nothing. CZ's are a proven design and very popular with the Comp guys for their accuracy and reliability. Mags for the Shadow 2 are easy to find and reasonable priced. If your willing to spend a little more and get one of the higher end models like the Accushadow or S2 Orange, you get a gun with tuned triggers, fitted slides and 1911 style barrel bushing. They can also be converted to SAO if you prefer or you can go with one of the Tactical Sport models (TSO or TS2) that come in SAO. I'm leaning S2O myself.