We've been using Netflix with just the streaming portion of the services and we haven't been disappointed. Netflix offers a large variety of shows and movies, but also has some pretty good original content.
We also just got a Roku because our Chromecast and Blue Ray player have been acting up.
There are several versions, so it would probably be a good idea to talk to someone about which would be best for your needs. It was pretty easy to install and didn't take much time. Once you install it, you can download channels to use. It came in handy during General Conference because they had the BYU channel available to download.
Although we did have to drop some money for the Roku, it is just a one-time payment. With cable, you have to pay a monthly fee. Overall, we really like using Netflix at about $10 a month and then the Roku for our other streaming needs.