I have sailed all the boats you list and they are all very good. Just be sure to read that link and check for all the serious defects listed in it. Most everything else can be repaired, but if something such as soft decks (hulls) are present you wont be able to repair it. I like prindles myself.

If you are new you probably want to read a book to get all the safety info. also post here we will be happy to help.

Formula 18 is probably too aggressive for a first boat unless you are already an experienced racer.