Good afternoon, all great questions to consider before making the decision. As an aside, I am in Ontario, Canada, so we do have to consider how to manage the ice. With that being said, so do people with lift systems.
For me, we have a bit of ice movement so I remove one section of track that goes between the water and land portion such that it mitigates any concerns with ice. I also have a friend with a setup such that the in water portion gets cantilevered out of the water during the winter. However, I do not need anything that elaborate.
My boat is not covered once it's on the land. Yet that me be a project for this summer, building a boat port on land. The key thing I love about the marine railway is it allows me to pull the boat out of the water ever weekend and then immediately wipe it down to keep the hull clean. Further, it protects the boat from being out of the water when I'm not at the cottage.
Mine is a Naylor system (I will send a separate note with the website) and it uses an electric winch to pull the carriage up.
The only issue I have experienced is with some rust and I then simply replaced a couple of the sections. Rather than buying the sections from Naylor, I saved a bunch of $ and bought U channel from a local metal supermarket and then made up my own sections.
Finally, I would endorse doing this route again.
Best regards.
Doug