With Sling, you can still channel surf, although you won't have as many channels as Xfinity (good and bad). You can sign up for HBO, Showtime, Stars, etc with Sling for an addition $10-$15 per month. I'm not sure how ppv events work with them though. I imagine they are there, since you can also do ppv movies through Sling.
Live sports are delayed by 5 to 10 seconds. With Sling, you'll have to choose between Blue(includes Fox channels) or Orange (includes ESPN's and Disney channels), or pay to have both. Then you'll want to add on the Sports package for $10 to get the PAC 12 networks. Even with all that, you are around $60 per month. I have been doing that during football and basketball season so I can get all the sports (ESPN, FS1, and PAC 12), and then remove one or more packages during the summer when I don't need access to it all to see the Utes play.