When I started in CAS a year or two ago, I thought that I could compete by point shooting with my pistols. I ended up taking too many misses and went to using the sights. I shoot duelist (one handed shooting category) and if you want to be competitive, you just can't afford to miss that often.
I shoot a pair of 1851 RM Conversions and love the brass post front sight. It points very well (as most say about the '51's) and that brass post just jumps out at me when I'm trying to take quick, but effective aim.
Best advice on getting into CAS/SASS is to go out to a local shoot. The folks will let you shoot their stuff, so you can find out what YOU like. That way, when you put out the gold dust, it won't be wasted on something that you end up not liking.
T6 a/k/a Chick