I use the 405 and it seems incredibly accurate everywhere except mountain bike trails with lots of tree coverage and tons of turns. Everywhere on the road, tree covered or not, seems really, really accurate.
I've used it on some measured trails/paths just to see if it's close and it was dead on with each mile marker. I also have mapped a couple runs using the usatf.org route mapping site, and again it's within a hundredth or two even over a 10-15 mile run.
As far as the "wet bezel" problem....it hasn't really been a problem. I like to see 3 things on my watch- total time, average pace, and distance. I have it also pop up the mile splits as they occur. I don't need anything else on there, so I just leave it on that screen, lock the bezel, and I never have an issue. It's really easy to use, too.
This is all coming from someone who swore these kinds of watches off a year ago. I finally broke down and got one so that I could more accurately measure distances of tempo runs and so that I could tell paces to the kids I coach as I run with them.
A year later, I do everything but races and track workouts with it.