I like endings that fit the themes and characterizations presented and provide a sense of emotional catharsis for the viewer. If they're predictable, that's fine as long as they do the above. If they're surprising, that's also fine as long as they do the above.
Consider three M Night Shyamalan films with Bruce Willis - The Sixth Sense, Unbreakable, and Glass:
The ending to The Sixth Sense is surprising, but it when it's laid out you see how well it fits with the elements of the story and provides a cathartic ending.
The ending to Unbreakable is predictable, but it's cathartic, fits with the rest of the story, and is executed well.
The ending to Glass is surprising, it's also stupid, unsatisfying, poorly executed, and leaves the viewer pissed off that the characters got fucked over for a pointless shock twist.