Hylander,
What are you IN TOO? You a competitive type? Or are you into "authenticity"?
If you're competitive by nature, go with the .357/38s. They are the most used caliber by the Top Guns in CAS.
If you are one of the authenticity minded folks then you will probably be happier with .45s. They are cool and easy to load for.
Bottom line here: Ya gotta decide wat yer wantin yerownself! Go to a mtch, ask to try some gunz. (most Cowboy shooters are more than happy let a new pard take some shots with their gunz!)
Regardless, if you really end up involved in CAS you will probably end up with a set of gunz in more than one caliber! :lol: I got a whole set of .45s and anuther set in .38 :shock: