Sky Q strikes me as a great piece of hardware that is ultimately pointless because streaming technology is about to obsolete it.
It's easy to stream from the internet to any of your mobile devices directly and the major broadcasters/channels either already have their own internet catchup/streaming or will do soon.
If you are a really techie person - who might be tempted by the technology - you can already set up your own home server and something like Plex and share downloads to home and mobile devices in a much less restricted manner.
BT have the right idea with an affordable streaming box/Youview PVR. They do need to get more digital delievery services onto it though. Youtube, Google Play and Amazon Prime for starters would make it more compelling.