Advantage to whichever feels best in your hand. This is the probably the only answer to your question..
Both are great guns. I have a P226 and a CZ 75b, and am a little CZ biased just because I shoot my CZ better. Why do I shoot it better? Well, mostly because it fits my hand perfectly. But the Sig probably comes with night sights, which is a nice attribute for a HD gun. As far accuracy and reliability...the difference between the two would be negligible to the point of rendering those issues meaningless in my opinion. These are first rate, battle tested service pistols; the world over.
If the cost is no deterrant and you've already handled both, I'd probably point you in the direction of the Sig 226. Night sights, a little lighter frame, nice trigger, well-balanced and durable gun. But like you said, you're splitting hairs here...so getting a good feel for each should be priority #1.