Here are a couple of videos of each. My husband had been to Saona, so I decided we should try Catalina. Everything I read said it was this beautiful pristeen island/beach. Surprise to me . . . I wished we had gone to Saona. Anyway, you can judge for yourself from Joe's Video.
YouTube - Saona Island Dominican Republic - by JCV Saona
http://ca.youtube.com/watch?v=anhscB4MpM4 Catalina
One more note, we could barely climb out of our boats before we were grabbed and hugged by vendors waiting on the wharf. The beach - you could pick a path through the chairs, broken glass on the beach and the empty beer bottles at the far end . . . I was surprised and disappointed. That's my experience. Next time Sanona for sure!
Cindy