GOG also offers a streaming option, ie. you can watch the purchased movies without first downloading them. So in a sense it is the best of both worlds, you don't have to download the full video before you can watch it, but you can if you want.

In comparison, Netflix is worthless for me e.g. at my summer cottage, as HD videos don't stream that well over a very slow mobile GPRS 2G internet connection. Or if I visit the rural area of Thailand. On the other hand, if Netflix offered me a way to preload a bunch of movies or TV series beforehand, in order to see them later offline... Hey, like GOG does!

The selection is crappy at the moment, hopefully there will be more interesting titles. Luckily GOG had sense to put the movies to a separate virtual shelf, I would have had an issue if they had been on the same shelf as games.

yeah I think it's not fair to start thinking GOG has to battle the big companies like Netflix, Hulu, Amazon etc.
What it does is something nice, and it's always a small battle won if they get a new interesting film added.
More the better of course, but I'd stick to the battles, not the war, for the moment :p