I dont think Airtel is the best, but one of the best. I have a dual SIM phone with idea and airtel connections. In city area, both of them gives me good coverage, but if you move to outskirts, Idea gives me better signal strength than airtel. Cost wise, both are having similar packages. On data tariffs, both has similar tariffs and both of them are yet to start 3G here. Edge speed of Airtel is slightly low compared to Idea. CC of both players are equally good. To summarize, both of them are serving me good, for my use. Disclaimer - Neither I am a propagandist, nor a blind supporter of any brand which I use. 🙂