For me, the best X-Men movie is Logan. I feel like a lot of people are gonna say this because it's just true. The movie is nearly perfect and ranks among the best Marvel movies.
The worst, in my opinion, is X-Men Apocalypse. This is for a multitude of reasons. But it's mainly because in a single film it managed to ruin all the good will the previous four movies built up. And yes, after we got Logan and Deadpool 2, but then Disney bought Fox and Fox coughed up the last two X-Men films.
What is your best and worst X-Men movie?