Id go with European History. I think I’d get bored in a U.S. History class in college because my teacher for it in high school was really good. I think it would feel more repetitive (especially because we learn about some U.S. history as far back as elementary sometimes). I’ve never taken European History so I may be biased to choose it because of that. But I would assume that since we rarely learn much of it in our entire K-12 education, you’d probably have a chance of learning more in depth about it in college since any info you didn’t cover in your AP class might be more new to you, whereas the U.S. History is more common so you might not feel as if you’re learning anything “new”. I don’t know, that’s just my opinion. You said you liked European History more, so it might help you stay motivated to do the extra work. It also depends on your overall course load for the semester.
It might help to look up the professors online and check their reviews. Ask past students about it, too.