juan, if you do a project from start to finish on 64-bit PI i guarantee you you will hit some bug or other.
last night i made a preview, dragged it to a new window, did DynamicPSF and then started experimenting with deconvolution. after about 15 applications/undos of deconvolution, PI hung up on me. i had to do the gdb thing. if you want me to start sending you stack traces when i do this, i can.
i'm serious when i say the only thing that makes 64-bit PI usable on OSX is the project functionality. when it gets into a bad state i save the project, restart PI and reload the project. otherwise there's no way i could use it because it would be just too painful to save all of my masks and intermediate images.