I've tried alot of the RPG's out there, both payed and free to play. And the difference is huge, those free to play games never match up. They are normally in beta, and therefore will lack content simply because of being incomplete, or just a hobby for someone to run and therefore lacking content because it's not seriously developed.
If you are truly interested in trying an MMORPG, go for WoW - yes it has a monthly fee, but it's not alot for such a high quality game that is being constantly updated with new content.