They have tons of bugs but the main ones, especially for watching sports:
1. Many games are missing the end or beginning. I understand that some games get longer than expected, but can; t they assign someone to readjust the actual play time? There are only few games a day at the most, and there is one recording for everyone (you cannot choose to add 30min like you can do with a normal DVR, only Sling can). A lot of games stop few minutes before the end at the cliff hanger.
2. On replayed games, Sling replaces the commercial with their own, and sometimes big chunks of the game are missing. Not only the commercial run over, they stitch it back missing entire drives and scoring plays in football. After the commercials are done, the scores are completely different.
3. On some channels, like comedy central, the Sling commercial start in the middle of the scene. And to make it worse, it resumes not at the same point, making it impossible to watch.
4. Some recordings will just not play. As a sports fan, I had to pay other subscriptions in order to see the same content that appears on my sling dvr, but won't play.