I have a couple Bushnell HOLO Sights. I can' t speak to the others, but it has never had a problem with wet weather. Plus, it is rated to be mounted on shotguns, handguns, or rifles. It will handle the recoil from even a 3 1/2" mag with no problem (and I have proven that

).
Personally, I wouldn' t consider using any mounting system other than a saddle mount. The reason is simple. When I first started using my HOLO Sight, I mounted it on a standard mount on my drilled and tapped Mossberg. I also made the mistake of installing the batteries that came with the sight from the factory. Needless to say, they died about half way through my second hunt. (No telling how old they really were having been packaged with the unit). Anyway, I actually had to call it a day as I no longer had any way of aiming my gun!
Unlike standard drilled and tapped or cantilever mounts, B-Square and Millet saddle mounts have a " see through" design that allows you to still use your bead(s) or fiber optic sights if something happens to the scope. It' s the only way to go, IMO. I have a saddle mount on an 870 and an 835 despite the 835 being drilled and tapped already. I won' t take the chance of being without a gun if anything ever happens to my HOLOSight, and you might want to consider the same with whatever scope you purchase.
Good luck this spring!