Rotten Tomatoes has Alita fluctuating back and forth just above and below 60% right now.
That's not "greatest movie of all time time" territory. But it's not terrible either. If it lands above 60% in the end it'll be labeled fresh instead of splat.
That neighborhood of 60% could change as more reviews come in. But with 140 reviews already, it should be fairly stable.
I need to decide whether to go see it in IMAX. The movie isn't in a taller aspect ratio for IMAX, but they use the taller aspect ratio for the 3D effects, allowing the things that jump out of the screen to go "above and below" the movie.
I'm probably just going to go see it locally in ordinary 3D. I'm not sure that the added effects are worth driving an hour in Michigan winter weather and paying IMAX ticket prices. But I'm still thinking about it.