First,
generally speaking, it is always nice to hold as many bullets as possible. Remember “10” is a forced limit from the Clinton era.
Second it depends on what you feel comfortable with, and how hard it would be to conceal and retrieve quickly.
There are a lot of great handguns out there. I personally have enjoyed Ruger’s firearms. I also like Smith and Wesson semiautos. Lots of people here like Glocks. I’d say test a few different models out. Gun stores that have indoor ranges usually have models you can use to test fire to see how you like them.
The bigger they are the harder they are to conceal. It may also make a difference in what kind of holster you’d have to use to conceal them more effectively.