Both are nice. Tough to compare the scenery, both are great. It was raining on us when we did Prince William Sound, and I got sick, but it was still gorgeous. Resurrection Bay had more interesting geological features I thought, and we saw more wildlife. Glad I've done both. While I may prefer the Kenai Fjords tour for that, we're actually picking up a cruise ship in Whittier because I liked Prince William Sound so much.
I was at Exit two years ago. The signs along the trail show how far it's receding, and it's sad. But I was thinking of hiking up above it to see the Harding Ice Field, which others on CB have highly recommended.