I am using 4G in Delhi but some place 4G is good, or most of place in Delhi 4G looks 2G. Airtel 4G is over all good comparing Idea 4G.
And about speed If you are expecting blazing speeds compared to 4g, then you are in for a disappointment. The download speeds are limited to 12-14Mbps in areas with full strength LTE signals. The 3G speeds range between 8-11Mbps under the same condition so virtually not much of a difference for the extra ‘G’