I tried Sling for a month on a Windows computer, and I promptly cancelled after that month. While watching a program, the transmission would stop and the following error message would appear on my computer monitor: "Due to inactivity, playback was stopped to save bandwidth." It took several e-mails to Sling tech support before I received a satisfactory explanation of the problem. They replied with "There is no way currently to remove the "inactivity" trigger (outside of pressing a button on your remote every once in a while)."
Essentially, the interrupted transmission meant that I was being punished for watching extended-length programs (3 hours or longer). That limitation resulted in many programs (e.g., most sporting events, live coverage of breaking news stories, epic-length movies, etc.) being cut off before the end. Since I was using Sling on a computer, pressing a button on a remote occasionally wasn't an option. In addition to the technical problems, there was no DVR feature on Sling at that time.
PlayStation Vue is a better value. I get over 90 channels which includes a greater number of news channels, sports channels, movie channels, HBO, Showtime, and many other popular cable channels. I also get on-demand shows from the 3 broadcast networks: ABC, Fox, and NBC. In addition, I get the CBS affiliate in my area, which includes local and network programming. The DVR feature is free, and the number of programs you can save is virtually unlimited. Vue can be used on up to 5 devices at once (a PlayStation game console is not required). The total cost is $54.99 per month (varies by market). That will increase by $10 when the introductory offer for HBO/Showtime expires after the first year.