Both Sigs & Beretta's are high quality handguns and I own a few of both. I'd be hard pressed to choose between my 92G & P226 Tacops as both have great features and are extremely accurate. One thing I will add is both are two of the easiest guns to break down, which makes maintenance & cleaning a breeze. It all comes down to specific features and how it feels in your hand. The finish on both firearms is outstanding as well... the beretta has more sheen (Bruniton finish) while Sig's (Nitron finish) is a subdued matte finish.
Best solution is to buy BOTH and enjoy each ones unique qualities and features... lol.