I ran the 6.5K in 2007 and the 13K in 2008. I liked both races but the improvements in 2008 were drastic and made the race a lot better. No more confusion at the start, much more happening on the course, more following with the Twilight Zone theming for the race. I like this race because it is at night and I don't run much in the dark. I also like it because it is near my birthday.
While the Disney races are fun, full of characters and have great theming, the food and fanfare following is what most do not rave about. The after party for ToT is expensive and the only bonus last year was that TSM was open and my family rode it over and over where you have a hard time even getting on during regular park hours.
Do some more research but I would do this race again if the funds were there for it. I would do it every year if I could!!