The macOS version of the Sky Go app has some major flaws that make it uesless imo.
The "Always on top" feature doesn't work
It doesn't work with full-screen apps (which, in macOS, occupy their own desktop).
The biggest use-case for the "always on top" feature is to watch something while I'm browsing the internet.
If I put chrome (or any browser) into fullscreen though, I lose the Sky Go app (despite "always on top" being enabled)
Quicktime player, which I use to watch TV / Movies also has an "always on top" feature that works just fine; i.e. it stays on-top of all full-screen apps.
You can't make the window small enough to be "out the way"
Even when I make the Sky Go desktop app window as small as I can, it still takes up more than half the horizontal width of my screen. I would say this means I can't use it with the "always on top" feature to watch some TV while I work, but I've already established the fact that feature is also completely broken.
These are both big usability issues for a TV streaming application.
I've seen the profits of BSkyB, surely they can take a pinch of that to make their basic applications fit for purpose?