Sling is just an app on Roku that gives you some live cable TV.
I prefer Roku because I use it for other things (netflix, sling, renting movies), but the delay for watching live sporting events sucks. I figured out it's for everything and not just the NCHC app because the delay was bad for the game last night too and the internet stream was even a couple minutes ahead.
You're almost better off hooking up the computer to the TV through HDMI.