Hi,
I have started using airtel 4G (1500 rs/- for dongle) from past 2 months and the speed is very good. And if I keep the internet on for the whole day, it never gets disconnected.
Pros:
Very good speed:
Download speed: 30 - 40 Mbps on nearest server and 6 to 20 Mbps on very far server. Which means you can download a file at the speed of minimum of 1 Mbps (because download speed is always 1/8 of browsing speed, it applies for any other connection).
Upload speed: maximum of 14 Mbps.(on average I get 6Mbps).
No disconnection: I have used other connections like Reliance, Bsnl, Tata Photon, Tata Docomo and MTS. If you leave the connection idle for 30 mins then your internet gets disconnected or your download speed will be zero if you try to browse (some call it dormant mode, you have to disconnect and reconnect to browse). In Airtel 4G lte I keep my net on always and some time leave it unattended for 2 to 3 hours. Still it does not get disconnected or enter dormant mode.
Cons:
Network availability: Airtel has not boosted up its 4G signal. So it is available mostly areas closer(say 30 kms) from the city radius. Or on the areas close to main highway.
My home is in old madras road 3 kms from K.R.Puram, when the demo person came he told I would get max of 10Mbps speed which he demonstrated also. After 15 days of purchasing the speed in this area increased to 30 - 40 Mbps on the same server which showed 10 Mbps. But when I went to my village 10 kms from here and 4 kms off Old madras road I did not even get 3G signal.
Price: Though the price seems to be reasonable the data package is not sufficient. That is 8 GB in 4G= 15 GB in 2G if you are frequent visitor of video sites like youtube. That is because If you are planning to watch just 2 mins video out of 15 mins video on 2G it would be still buffering and you will be able to close the video after 2 mins and the whole video would not have buffered whereas in 4G the complete video will be buffered within minutes. Hence data consumption will seem to be fast (no cheating involved by Airtel if you are seeing your data consumption if very fast).
My suggestion:
If you are looking to buy Airtel 4G, I would not suggest you to buy it from the Airtel store, because they just sell you the dongle or router without knowing the connectivity in your area. Call Airtel customer care or got to Airtel website and ask for demo at your location. Opt for it only if you are satisfied with the demo. No point in blaming about network connectivity if you buy dongle without a demo.