The key to me is whether or not water is contained. I've seen some European showers where water goes everywhere. In fact, I've been in European bathrooms where there is no "shower;" the entire bathroom is the shower, and everything in the bathroom gets wet.

I recently built a shower at home that just had a half wall and no door. It keeps the water in and I've been happy with it. You can click here to read about it and see the photos.