I've seen Frozen... hmm, about a month ago, and Tangled the other day. Frozen, on one hand, isn't bad, not by a long shot, but it was still kinda forgettable. @Twilight Lunabrings up a good point how it worked around some of the usual Disney tropes, but the story suffered despite, or maybe because of that. We've got double the princesses, double the villains, a ton of songs... but none of those really stand out. The Weaseltown dude is just kinda phoned in, Bait and Switch could have been interesting if we got more time with him - there's too many characters being juggled so the soup is too thin to care about any of them. Likewise with the songs - I think there's at least a half-dozen of them in the movie, but I can only remember the song and... something about a fixer-upper?
Tangled, on the other hand, is a lot more tightly written. We've got our trio of main characters - Rapunzel, Flynn and the witch, with a bunch of fun supporting characters that don't overstay their welcome. Not as many songs, but they stick out a lot more, though presentation also helps a lot. Not to mention Mother Knows Best pretty much seals her as a villain I just loved to hate. Plus the comedy is on point, especially the physical aspects.