It depends on how much I like the game generally and how many endings there are.
Something like Dishonored is a joy to play whether you go quietly or bathe in the hot blood of your sundered foes, so playing it multiple times to get different endings was great. Dishonored 2 was even better in this regard because it added the choice of protagonist which, thematically, gives the game four different stories (arguably six if you want to go a little deeper).
Some games, though, just have too many different outcomes. Not necessarily in terms of 'main quest' but with regard to side-quests, optional stuff, and all that. Games like Arcanum have so many different outcomes to so many different situations that each playthrough could be unique, but going through again and again to see them all would be exhausting. It's a point in those games' favour, but it can be a bit frustrating for someone like me who wants to know all outcomes as soon as possible.
Visual Novels are a bit funny with this kind of thing because so many let you fast-forward through dialogue you've already seen, so going through again to get different endings can feel pretty perfunctory rather than fun.
Overall, though, I think alternate endings can be pretty fun and I do like them, just as long as seeing all or most of them isn't a massive slog.