Whoops! I somehow read "Magic Mountain" rather than "Universal" when I first replied.
Short Answer: if you are a movie fanatic, then the studio tour might be enough to make you visit USH. Otherwise,
especially coming from Canada, I'd get a taste of the Old West at Knott's.
KBF has changed in recent years to be more like SFMM-type parks, but still has theming that is unmatched anywhere (and yes, that includes any Disney park on the planet). If you had a choice, I would visit during the Christmas season. The web site does not have good information on entertainment schedules, but there is an ice show running for much of the year. There are also performances by both cowboys and Indians - Mystery Lodge is one-of-a-kind.
(You didn't ask, but just in case ...)
SFMM has more high-thrill roller coasters than almost anywhere else. If X2, Viper, Tatsu, etc. are not exciting enough for you, consider becoming a test pilot.
Although it is supposedly a "theme park", the term is really to distinguish it from "run of the mill" amusement parks. It's often closed on weekdays, so be sure to check the calendar on the web site. Entertainment is sparse, especially during slow season.
See some of my photos on
this thread.