This post makes me very nervous!
I've been promising my family that US is not a "Six Flags" type of park (no offense to 6 Flags lovers- just not enough theming/not clean enough for us!), but this post makes it sound similar...
I know everyone has different experiences and we will be staying onsite(PBH) and that might make a difference...
This is our first trip to US and we aren't sure what to expect. Anything you can suggest to prepare my family for a fun time? I'd hate to come home disappointed too ...
I'll be going to US for the first time this December, but I'm not too worried. Mainly because I've read similar rants about Disney parks - someone will go and then come back to these boards and post that the park was dirty, the crowds were horrible, the magic is "gone", and cast members were rude.
But I did my research both times before I went to Disney and we had a great time. I even managed to make the Disney Christmas Party bearable for my crowd-phobic husband. No regrets!
I've never been to US, but I already know not to expect much from Sinbad - the Unofficial Guide says it's definitely one you can skip. I also know that the Revenge of the Mummy is going to be great.

I know that I hate lines, so that's why we're staying onsite at the RPR.
Dirty... well, that depends on your standards. I've been looking at a lot of tourist pictures of Universal lately - it looks lovely. Much cleaner than Canada's Wonderland and much, much cleaner than the Central Canada Exhibition (which always smells like garbage).
Bad luck can happen to anyone. I was stuck in a Disney monorail car once with a kid who kept puking on the floor. And then the monorail itself got held up for 15 minutes on the line, while we're all dying inside.
As for coasters - we're not big coaster-fanatics. We like shows. And concerts. And dark rides. And educational stuff. We like poking around and looking at things. Some people go tearing through Animal Kingdom in two hours and then complain that there's nothing there to do. For us, it's a two day park, at minimum.
So, I've never been to US, but I'm quite sure we'll have a great time!