I use it as my low cost HTPC, I have XBMC sideloaded and the micro USB connected to my powered USB hub. I connected my wireless mouse and min keyboard, USB memory stick, and external powered hard disk to the hub and they work great.
By sideloading some apps I also have access to google drive and network share. So far the device has lived up to its specs.
I believe you have to realize if you get this you are an early adopter (whether you know it or not), but also believe the huge google ecosystem will deliver lots of apps and hacks to really take advantage of this little device. I have been reading that root access is not far away for people that like to tinker.
For the leanback crowd I trust devs will be releasing lots of apps, as this is a pure android version that will be upgraded over time.