my SuperHub (I think it's a 2) used to work just fine, but recently started to become unreliable. I have to re-start it frequently, sometimes it drops speeds to a snail pace, sometimes it stops connecting to the Internet altogether. Unplugging and plugging back in always fixes it.
This sometimes happens several times a day, sometimes it works fine for a week or so before I have to re-start. Up until a few months ago I never had to do this at all.
I use the router in "modem mode", with a wired connection to an ASUS router.
The WiFi connection to the router is not an issue, nor the Asus router's connection to the SuperHub, only the Super Hub's connection to the outside world.