They offer Disney, TLC, ESPN1 & 2, Lifetime, and about 10 more stations (plus Starz if you pay an extra $7 per month) in certain areas. The SLC area is one of them. I think currently there's two others, check their website. Of course, they plan on "upgrading soon!" to everywhere else, lol. They basically broadcast it all like any other tv station, but your reciever needs to be authorized to get their stuff.
According to the people on the USDigital support line, the $20 and $200 versions are the exact same box. The hardware is identicle. The only difference is the software. The $200 one is USD "ready," meaning it works right from the start to recieve OTA stuff, but eventually can always subscribe to their service as well. The $20 is the "subscription" software, that forces you to call and sign up to use it. Once you're signed up (even if just for 1 day of the 30 day trial) you can always cancel, then use the $20 box as a standard OTA reciever.
I did a bunch of online research when I first got mine, and found out there was an ebay scam some time ago where people were buying the $20 versions and selling them on ebay for $189. The poor suckers who bought these complained to USDigital, who sent them out little 32k USB memory sticks to plug into the back of their unit that flashed their software over to the $200 version. Too bad they made them send those little USB drives back...