What I always disliked about jQuery UI is that it's horribly annoying to change the CSS, and also the fact that it adds classes using JS. Bootstrap sort of fixe

What I always disliked about jQuery UI is that it's horribly annoying to change the CSS, and also the fact that it adds classes using JS. Bootstrap sort of fixes that problem, but they (personally) have odd naming conventions for their classes, other than that Bootstrap is alright.