Sling is getting a lot of attention, but if you follow the forums / Reddit it has loads of complaints. Biggest is stuttering, and channels not playing or available.
If you looking for options USTV Now has my vote. I currently am trying the $19 a month promo that includes over 28 channels. It is so Chromecast friendly, the quality and performance is impressive.http://www.nateschmolze.com/2016/01/sling-me-on-over-to-us-tv-now.html