See my earlier post re Harmony Remotes.
I've had issues when trying to use the Sky Q app in the home , the app reports you are no longer connected to your Sky Q box requiring a reboot of the STB.
I've had an instance of no tv guide on the mini requiring a reboot.
I believe there's an update in the pipeline so hopefully these bugs will get fixed , personally I wouldn't go back to Sky+HD as we find Q suits are needs better.
I can 100% assure you Sky are aware of these issues and actively looking to bring a fix out.
I've seen people saying they've had issues with the connectivity of their Mini boxes however so far mine have been fine both via wifi and homeplugs.