The quick, all-encompassing answer is that Slingbox is a Television. It has the same capabilities and limitations as a normal modern TV. The only substantial difference is that Slingbox has no screen- it borrows your computer for that.
It's a cool piece of tech, and there's definitely a lot going on behind the scenes... but in terms of function and practical use, Slingbox is a TV.
Slingbox Pro HD Input/Output Ports - Click to Enlarge
Will a Slingbox act as a tuner?
The Pro HD model will, yes. Sling Solo, no. The Pro HD's tuner can handle NTSC, ATSC and Unencrypted Digital Cable (Clear QAM). If you're in broadcast range of your local TV stations, hook an antenna up to the RF input and it'll grab whatever TV it can find floating through the air.
What features will I lose from my set-top DVR?
All of them, except for the on-screen "TV Guide" grid. Remember, Slingbox is a TV. If you're using the Web Player (watch.slingbox.com) or the Windows version of the full SlingPlayer program you will have an on-screen guide window. It's a fairly typical grid with channels down one side and times across the other. If you click on a show that's on the air, the Slingbox will tune to it.
Two things you didn't ask about that you might like to know...
- Slingbox can control many types and models of source devices using its IR Blaster. For example, if you add a DVD recorder or standalone DVR like this into the mix, there's a good chance the Slingbox can control it. Like a normal TV, Slingbox can't record or play discs by itself. But it will gain those capabilities if you connect devices that can. Just so you know, there's support for loads of devices but not ALL devices. Here's a link where you can check compatibility:
- Slingbox can't access or stream online video content. But it can stream and control properly equipped computers that do. If you have a Mac with Front Row and an Apple Remote for example, you can hook it up to the Slingbox. Support for that is already built into the Slingbox and Player. Anything Front Row can do, you can sling. That means...
- Anything in your iTunes, iPhoto and Aperture libraries
- Anything your Mac can play in the Movies folder
- Anything on network shares that Front Row can get to and play
- DVDs & CDs inserted in the optical drive
- Hulu & Netflix (via Front Row Plugins)
...in addition to what you can watch over the Antenna and other more conventional source devices.
(It's possible to do these things with a Windows computer, but it is typically more difficult.)
Hope this helps !