There are some FFs that are good and some that are not so good. But of course, which ones change depend on who you talk to. I think the series is the most recognizable of RPGs simply due to its extensive success, the movie that was made (flop or not, it still got coverage).

Regardless, my favorite RPG all else considered is still FFVII, and others from the series still rank pretty high up there in my list of good RPGs. But I agree that playing FFs does develop a kind of tunnel vision in most people, that once they've experienced FF they don't need to play other RPGs because they already have the best possible feel of the genre.