re bindings, Ive used bog standard Salomon stuff with the pins, step in ones, for about 20 years, and you know Ive only had problems with them a few times. Those times were from going through some actual wet areas where water got into the binding. Its pretty darn rare for me to ski or walk through wet stuff, so Id have to say the click in stuff has been very reliable.
Are the three pin stuff still sold for this reason, less gunking up of the binding? I ask that but then I recall times where wet snow has accumulated in 3 binding stuff and it being hard or impossible to clip them down. And wouldnt water turning to ice in boot "holes" be more of a pain to clear than the relatively easily accessible pin area (you know, using a pole end tip)?

I guess it comes down to boot construction, but the fact that 3 pin stuff is still sold means that it does the job for people.