Shutter lag is not the only thing...
I own and use a 5060 with a PT020. The housing has some design faults and the camera's autofocus is no good, but I have not found an alternative yet that doesn't have other faults.
If I were to buy a camera today the 5060 would be on my short list. I'm also eagerly waiting to see what housings will appear for the Nikon 8400, and I'm guessing the Sony DSC-P150 (or the V3) with a wide-angle converter could be an alternative.
Some things the 5060 has that will be hard to give up:
1) 8 programmable user settings, including a preset manual focus distance, that can be easily/swiftly switched between.
2) The built-in strobe can be set to slave-triggering mode (reduces "snow", saves battery, generates less heat...).
3) Very good battery life (reduces the risk of flooding and fogging).
4) A decent wide-angle lens. (It's as wide as it can be without using a converter and/or a dome port.)
/Anders