I have a silicondust HD HomeRun Prime instead of a Comcast set top box. Is Sling compatible?
Check http://support.slingbox.com/get/KB-5000164 If it isn't supported I can probably build you a Custom Remote.
If I have a new Samsung smart TV at the rental property, in theory I should be able to put a slingbox at home, load the slingbox app on the rental property TV, and the one cable account feeds both properties.
No, As far as I know there is no app for a Smart TV. The system is based on you viewing the stream on a PC or a Mobile device, phone/tablet. If you want to view on a TV you need to get an additional device such as Roku (still needs an iphone), WDTV, AppleTV......
Both locations could view programing at the same time, since there are 3 tuners on the silicondust device. Do I have that right?
The silicon dust HD HomeRun Prime has 3 tuners, and the rental property has 3 TVs. So it seems possible that the rental property could take all my available tuners and leave me with no tuners available at home... Or if I'm watching TV or recording multiple shows, then the rental property could be blocked.
Almost certainly not. On most boxes I know of the multiple tuners are solely there so you can record other programs while watching another. Like your TV, the Slingbox can ONLY access whatever signal comes out of the back of your Cable box. And I suspect that is a single channel. And if you are watching a channel that is the ONLY channel the Slingbox can stream to your other property. if you want to stream a different channel then the Slingbox will need it's own, dedicated cable box.
And even then, only one person can watch the Slingbox stream at any time. So you can forget having 3 users.
How reliable is slingbox? If the renters TV is always going down, them being out of state it could be very disruptive.
It's good,although like many electrical things these days it occasionally requires a reboot. But as it is sitting next to your TV that is fine.
I see in the forum that some people have set up Sling in their vacation properties.
Sorry, you are missing the whole point of the Slingbox. You don't 'setup' a Slingbox at your vacation home. You 'setup' the Slingbox at your main home and then you can watch your TV ANYWHERE in the world. Your vacation home is simply somewhere where you can login and watch, the signal is available wherever you are, coffee shop, hotel, airport, friend's house.................
Make sense ?