I've been using SNNow for a few years since I don't watch any other TV.
In my experience, it's about 20 seconds behind TV or radio watchers/listeners and for whatever reason, I only get 720p or lower. It's fine for me though, I just watch on a 24" monitor, so I don't need 4k or anything.
I've heard tons of complaints about the app, but if you simply watch via a computer and not a phone app (connect via HDMI to a TV if you like), it seems to work much better. I've never had a single blackout for Canucks games here in BC.