I own a Sig Trailside and a Browning Buck Mark. The Sigs are no longer made, but you can still find them new and they are just fantastic.
I enjoy the Browning as well, but the balance and accuracy of the Sig are superior in my opinion.
I don't own a Ruger 22, but I know they seem to be the most popular. The only one I ever shot was a beat up rental at a gun range.
Also, I know there have been reliability issues with some of the Walther P22 and Sig Mosquito guns. Some love them, but others call them jam-o-matics. I guess its just whether or not you get a good one.
No experience at all with the Smith or Beretta you have in your poll. I own other Smiths (M&Ps) and other Beretta (Tomcat, Bobcat) and they are all excellent pistols.