I recently bought three 43" 4K TCL Roku TVs cheap (under ~$225 each). Have set up 2 of them, one with a desktop for TV + monitor use, one for just TV and movies + Roku streaming.
I signed up for a 14 day free trial of Sling 4 days ago! I tried Sling a year or two ago but the streaming just sucked so I quit immediately. This time, with the Roku TVs it's not too bad. My <5Mbps DSL doesn't help, but gigabit is on the way when my ISP gets it together here, which should be any day/week/month, who knows (they promised last October).
What's the deal with Sling? I streamed TBS NCAA basketball games Saturday. The quality wasn't as good as OTA HD (i.e. CBS), but it wasn't horrible. I had expected to be able to use the Roku PAUSE/REW/FF 90 minutes feature of the TCL TVs, but get the "not supported for TBS" messages. I tried ESPN 2 days ago, same deal. I get the impression that TBS, ESPN (and who knows who else) have made deals with Sling to provide content with the proviso that you can't DVR them. Actually, the first thing I did when I saw the "not supported" messages was sign up for the $5 DVR feature, thinking that would solve it. But it didn't! I don't even know how to use the DVR feature, but I signed up for it. Have to investigate. Do you have to watch AFTER the program completes?
If I can't get some satisfactory DVR functionality out of Sling I think I'll have to cancel, at least after the NCAA's, or maybe the NBA playoffs. I hate commercials!!! Almost always.