Should I see Ponyo or Harry Potter in IMAX?

My friend Aadil and I are trying to decide whether we want to see Ponyo or Harry Potter in IMAX. The thing is he has not seen either one, but I have seen Harry Potter already. I want to see Harry Potter, but I also want to see Ponyo. Here is some information on both:

-Ponyo is an animated film about a goldfish who wants to become human, but her dad does not want her to become human. It looks like a really cute Disney film, but it has a high potential for being lame or cheesy.

-Harry Potter is a movie based on the sixth book in the Harry Potter series. Everyone knows Harry is a famous wizard and has to defeat Valdemort. BLAH BLAH BLAH! I do not need to go on because we all know what Harry Potter is right? Right.

We all know that Harry Potter has just come into IMAX, so it must be more fun in IMAX right? So should we see Ponyo, which is not is IMAX, or Harry Potter, which is in IMAX?