I am using Airtel Postpaid business plan 1599 from last six month, they offered me about 800 different packs including STD Packs, ISD Packs, 3g Packs, 2g Packs and Roaming packs.
I have chosen all packs according to my needs and I am happily using all these packs from last six. 3G Speed is outstanding, I used to watch videos on Utube without buffering at high quality.
Apart from usage customer service is also very good they inform me about billing and payments regularly on time and they always process my requests as earliest as possible.