I've had mine since December and I love it. Goodbye hard drives!
Mine is plugged in behind the TV and the modem is about 2 metres away on massive wireless speakers. I get on average 15-20Mbps speed at home and I've been streaming HD content effortlessly with no lag what so ever. Mirroring from my Nexus 6p is a breeze as well. Also I didn't need this device as I already have a smart TV, though this trumps that now.
I think each user will have a different experience. In my opinion, I highly recommend it.