I think Sling worked out for me last year, though admittedly I watched most games via WatchESPN on playback because I was at the game. From what I could tell ahead of time, all games were either local TV in ATL or on FoxSports or an ESPN.
I had some issues with wifi, however after I hardwired via ethernet the stream has not had a hitch. I'm not sure if my issues were Sling, my wifi speed (60mbps should be good enough), my Roku, my Roku location relative to my wireless router, or something else. In any case, most recent data point is World Cup was flawless streaming via Fox Sports app and hard connection to my router.
Anyone try YouTube TV?