It's a personal choice. Reunion is more expensive. It's very stable and has great features. MacFamilyTree is cheaper and I felt less impressive for my requirements. That said, my husband loved their 3D report.
Download the demos, play around with them. See what you like/dislike about them. If possible, use the same GEDCOM to compare how they work with your file. I also tried iFamily for Leopard.
Best of luck.