I did a Panama Canal crossing in '98 on a HAL and LOVED IT! When I wasn't on my veranda, I was on deck or in the Crow's Nest. Going thru the locks on the Pacific side we were alongside a Crystal ship - we were all waving at each other and looking into each other's suites and toasting each other with Bloody Marys (it was morning!).
I would do it again in a heart beat.
I did the Suez a couple of years ago and although it was interesting (from a military sense) it wasn't as beautiful.
Scheduled to do the Corinth Canal next year on Seabourn - something I've wanted to do for some time!