Catalina's, Beneteau's and Hunters are pretty much the (no particular order)Ford, Chevy, Dodge of the sailboat world. Pretty good for their intended use (ie the type of sailing you are contemplating) but built with compromises to make them affordable to us mortals. Personally, I've come to like the Catalina's the best of the three with Bene's a close second and Hunter a very distant third.
I'm not sure if you are buying new, but since the 309 is a newer model, I'll offer that you might be better served to buy a used boat as a starter and let someone else take the depreciation hit. I think a newbie getting their first boat exactly right for them is something of a long shot since there is so much you don't know. Getting over the "paralysis of analysis" and getting started learning is the most important step.
Full disclosure: I'm a newbie sailor, so I'm not drawing on a lifetime of sailing experience for my opinion, however I recently went through the process you are going through myself, so I hope my 2 cents helped.
This website has model info and owner reviews for the older Catalina models:
Catalina Owners.com for owners sailing production sailboats