It's not depend of Roku, it's depend of channels.
I was using my Roku in Russia, Netflix was russian, some of channels was unavailable. But in general the roku was working good.
Plus it was Roku 1, so i did not have any problems. It was working well with Old TV

I've just checked web-site of one of company and there is information that they will stream Rio 2016 on Roku, but i'm not sure if it gonna be en English. On Russian for sure, so it's good time to start learn Russian. The subscription is much cheaper

I've just subscribed to Russian Roku Channel
First month fro free, a lot of channels, there are 5 or 6 movie channels and some 18+. Not bad for 7.99 a month.