We used the FITS passes in December, purchased through Paramount Travel. We had a bit of trouble redeeming the vouchers at Epcot's Guest Relations (outside the gates). The CM was reluctant to issue them to us because we were from the U.S. and she had only seen foreign tourists with them. The situation was finally resolved and we were given our tickets (I showed her the receipt for the purchase from Paramount), but we were worried for awhile! Actually, our problem is the only one I've heard of here on the boards...everyone else seems to have had no trouble at all. We thought the FITS passes were an excellent deal. Sorry I can't tell you about Ticketmania, though they have a good reputation and I wouldn't hesitate to buy tickets from them.
Boy, do I wish I was in Hawaii right now---I grew up there but am now in Michigan. Today is awful here...snow and very cold!!