I've subscribed to Sling TV for about a year, since it became available in early 2015. It's been a bumpy ride, with technical problems and customer service issues, but for the most part I'm glad that I had it. Now, though, I've decided that it's not worth the monthly subscription fee to me.
Sling TV is basically like a cable TV subscription without the actual cable. You choose a package of channels for a monthly fee, and you can add other channels for an extra charge. You watch your shows via an app on your computer or phone or other media device. (In my case, a Fire TV.)
When I first subscribed in early 2015, the technical problems with Sling TV were legion. Sometimes I couldn't connect at all. Other times shows would stutter, or stop playing in the middle. The Fire TV app interface was terrible. I stuck it out, though, in large part because the baseball season was coming up and I knew there would be plenty of games on ESPN. By mid-summer, the technical problems were significantly reduced. There are still occasional problems, but now they're the exception, not the rule.
I also had some customer service troubles. I originally signed up with a two-week free trial offer that Sling TV was running through Amazon.com. When I decided to go ahead and subscribe after the trial, I kept getting errors. I had to call customer service several times, and eventually just close the account completely and set up a new one through Sling TV directly (with no Amazon involvement). It was just as difficult to add HBO to my subscription a few months later (at Game of Thrones time, of course). Again, things did improve. By the time I cancelled the HBO portion around the end of June, I was able to do so via the website without major difficulty.
So why am I dropping Sling TV now, if things are better? Mostly because I just don't use it enough to be worth the monthly fee. The only channels I really watch are for sports (EPSN, sometimes TBS). I watch a whole lot of video, as anyone reading this blog already knows, but the vast majority is either over-the-air channels or streaming services. If Sling TV had some other sports content, like FOX Sports (mainly for hockey) or the MLB/NFL/NHL Networks, then I might feel differently.
Another reason for dropping the subscription is the lack of DVR functions for the channels that I watch. There's no recording of shows to watch later, or even short-duration pause/rewind of live TV. Twenty years ago, that would have been fine, but now? That sort of functionality is pretty much the standard these days. I rarely watch any non-sports event live, and I make heavy use of pause/fast-forward/rewind even during live events. Lack of those features lowers the value of Sling TV significantly for me.
I might think about coming back around next fall, when football comes back on, since there's a whole lot of college football that's exclusive to ESPN, as well as Monday Night Football games. But until then, I have other sources for my hockey and baseball sports fix (mainly Internet radio) and nothing else that's worth paying a monthly subscription.