Mike, I have used peco switches and flex track for years and highly recomend them. I go to swap meets and pick switches up at reasonable prices sometimes very reasonablely priced. I presently use code 100 peco switches, I will eventually be replacing them with handlaid code 83, as I use handlaid code 83 for most of the layout with handlaid code 70 for sidings and spur tracks, but as I have numerous code 100 peco switches to use for now, and to get things up and running, I make use of them.
Our club uses nothing but peco switches and peco flex track, all code 100, for the main lines and sidings. We will use code 83 and 70 for industrial spur tracks.
As to your third question, just about every hobby shop that I have been in carrys peco switches but as I stated look around and you can find some great deals at swap meets. Check out some of the adds in the railroad mags, they offer some good prices for peco. Ron..