While we're on the subject of Plex, there's another option called Emby. See
www.emby.media
Similar to Plex, Emby consists of a server that stores/accesses ripped movies (ripped from DVD, BluRay or downloaded from Amazon or whatever), and any number of clients that actually display the content.
So, the server can live in a big ugly box of a computer in a closet somewhere, and you can have a Roku or a small home theater PC close to your TV to actually play the content. OR access the content via Android or iPhone apps, or just about any DLNA -compliant device, or... there's many different apps for all kinds of different hardware. Plex versus Emby is for people kind of a religious war like iphone versus android. I've tried both, and settled on Emby. Actually been using it since 2009 way back when it was called Media Browser.
I rent content from the usual sources in the form of DVDs and Blurays, rip the content to MKV files (using a tool called MakeMKV), then store it on my server until I watch it. Point of ethics here: I pay for all content I watch, and I delete it after I watch it if the content is rented instead of purchased.
Emby also supports recording TV from off the air sources, typically via an HDHomeRun network-attached tuner. The Emby Server software will let you download a TV guide, and you can pick what to record and when... your standard DVR application. It works quite well. If anybody is interested in more on Emby, let me know. But I don't want to threadjack here... start a new thread.
I also have a Roku, but don't use it much because both my TVs are smart and have the NEtflix/Amazon/Hulu apps I need to stream. I use the Roku when traveling. My dad, who has two "dumb" TVs, has a Roku on each TV. He loves the British TV channels (Acorn and Britbox I think they are).