The typical setup (from my experience) is to run JRiver on a computer that is left running 24/7 (the "Server". This is where the MC "Library" is located. The actual media can be on this Server or a NAS or wherever) and that Server computer has the TV Tuner cards. Then you put a small PC at each TV (the Client).
The Client computers will use/share the TV Tuners on the Server.
You can watch multiple channels at the same time on different Clients (if you have multiple TV Tuners on the Server), set recordings and subscriptions from any Client, watch movies (multiple Clients can watch different movies at the same time as long as you have the network bandwidth), you can listen to audio, etc.
Clients can pause Live TV, have RR FFW features. You can also start watching a TV show and then later, at the end of the show, decide you want to record/save it and MC will save the show from the beginning.
I don't use Android or iOS devices, but they work too - as others have posted.
Just be aware that JRiver can't do "Copy-Once" programs, so if you have a cable-card and your cable provider flags the TV channels as Copy-Once, JRiver is not going to work. But JRiver has Kickstarter campaign open now to see if they can raise enough interest/funds to add this feature (licensing fees are high) but this feature won't be added unless there is enough interest.
