I have been using Airtel 4G Router(not the pod) for 10 months.There was only one downtime during this time. So, 5 stars for connection reliability.
I took 20mbps plan. The speed I get matches that.One has to check the reviews based on the area. Mine is Indiranagar, Bangalore.
HD video streaming on my chromecast works fine. Only, the data is consumed very fast. I wish there was a setting in chromecast to use lesser resolution. It automatically picks highest resolution based on speed.