We've bought lots of plastic wine glasses for outdoor use over the years, and these are, hands-down, the nicest. These are heavy and substantial feeling, with no rough edges around the rim. There is a visible seam, but it's understated. The clarity and refraction of the plastic is really stunning, in some ways more attractive than glass. These glasses are on the large size. I can't say how they will hold up in the dishwasher, because they're too tall to fit on our top rack.
Overall, I am quite impressed, and we will be buying more.