If you are limiting your choice to these two, I would lean toward the Sig's. The Beretta's are fine weapons but I personally believe the Sig's are a better made production pistol. I have owned and carried both at some point in my LEO career. I have never seen problems with the Sig's, but have seen several with the Beretta's.
Like you, I'm not real fond of the ergonomics of the decocker on the Sig's, but the grip is much better than the Beretta's for me. I personally believe that Sig makes one of the best production pistols available. I have been carrying the 1911's for the past 10 or so years and find it to be the best for me (not knocking the others, and I've carried and owned many).
Shooting the Sig: I find the recovery much better on the Sig than the Beretta, which probably has to do with the grip ergonomic's mentioned earlier(but I have medium to small hands). For me the 1911 platform is the only choice, but as was stated earlier, weapons and shooting is an acquired taste and they probably will change over time.
Sounds like to me, you have really already made up your mind popo22... Not to worry though, with the two choices you've narrowed it down to, you can't go wrong...
My self, I'm a Sig man... But someday, I'm going to own a classic 92FS...(Yes!)
Both pistols are top shelf. I've heard good and bad about both...
My Sig's have been flawless, but so has my Buddies Beretta...
I too enjoy the SiG line up. I found that for my hands the SiG pistols have the best ergonomics. There are a lot of fine firearms available on the market but they are worhless if they don't work for you. I have found my match with SiG.
I had a 92FS for 8 years up until a few months ago - I sold it so I could have money to buy something new. I kinda changed up my whole collection in the past 12 months.
The only neg thing I can say about the beretta is that w/ the open slide, U see the wear on the barrel pretty quit. Kinda sucks if U are a big "try to keep the gun from getting scratched" person like me