Our 1st WDW trip is coming this summer, so I am not able to compare benefits of US over WDW. When we did US we only had 1 day there but with Express Pass we were able to get on to everything so quickly---highly recommend staying on site for this terrific perk. Anyway, our 3 kids were 6, 9, and 12. They (as well as me & DH) really, really loved US. Shrek and Jimmy Neutron were great. MIB was REALLY something as was Back to the Future and the Terminator. We did these attractions each many, many times. (didn't have the Mummy yet when we went). Unfortunately we couldn't do the Jaws ride because it was raining/small lightening concern so they shut down that boatride. DD 6 loved the ET ride/show, older 2 kids thought it was too "childish". (We also did others such as Twister, Earthquake, etc. which were ok but not stellar) Can't remember ages of your kids, but I just have to say we all sure had an enjoyable and memorable day when we were there.