I think Sky Q is their next generation box to replace Sky Plus HD equivalent with added features so you can view on other devices such as tablet in other rooms , it says it acts as a wi-fi hub which suggests you would hook it up to Sky Broadband [imagine other providers will be catered for eventually] and it would do the same job as their router. The blurb says it starts at £54 a month then you build your package , at further expense, to tailor it for your needs.
I have Virgin Tivo and use an app on my tablet, TV Anywhere, to watch selected channels but I cannot seem to watch any recordings I have on the main box . Sky Q implies you can not only watch your recordings on a remote device like a TV in another room [imagine it would have to be a smart TV with a Wireless ethernet card so you can network with the main Q box] or a tablet but also download them to a tablet or laptop so you can watch them offline elsewhere.
The problem is what is the cost of tailoring the package to get these features. If you already pay for Sky then it may be worth an upgrade cost for added features but if you don't have Sky then switching to their broadband [to get full service immediately] and taking their Sky Q package could be prescriptively expensive.