My family & I have gone to this festival 3 or 4 times. It's a lot of fun, and I've never failed to learn something new. Although it is an accordion festival, polkas are rare, and most of the acts are folk, folkish, or ethnic. (The only regular clunker is Dick Contino doing what could only be described as a Vegas lounge act for the over-60 set. Why why *why* do they keep bringing him back?!)
If you are one of those with questions about free-reed instruments, this is the place to go to get answers, too. Lots of dealers, enthusiasts, etc. around.
Caveat: besides Dick Contino, the only drawback is the festival's inside-jokiness, such as the Lady of Spain-a-thon. There is good music here too.
doug aka darkriver (I dunno if could be called a 'Catter--I'm not a musician, only a music lover. Been mostly lurking this past year and asking a coupla questions. BTW, my actual name is Doug; I picked 'darkriver' as my cognomen because someone else took the name 'Doug'.)