There's the YouTube app. Lots of illegally uploaded movies there, like these:
The PS movie section has a lot of good movies. The download times seem fine to me with ethernet. Best to rent because it's expensive to own and you don't get to re-download if something goes wrong, but you only get 24 hours to watch it once it starts, which means if it's long and you start it late at night you gotta remember to get back to it.