Eisenglass is a great material that can withstand most of the beatings that offshore fisherman put their boat through. The problem with too much eisenglass is keeping it clean and functional.
We have found that over the years that zippers and stitching need to be replaced and this is why many sportfish boats prefer to have glass. No matter what the quality of craftsmanship involved, we have yet to see a curtain that is several years old in tip top shape.
Some fisherman will build pilot house enclosures out of eisenglass as a nice dry area to operate the boat. This works out great and withstands speeds of 20 knots or so no problem. The pilothouse works out great in rain or rough seas.
If you are going to be replacing your eisenglass, we suggest you get several quotes as the prices vary greatly from company to company.