I have one aircel sim as my secondary contact number. call rates are low in aircel and so is network strength. if I go outside the mumbai like khdawli etc network goes completely. even in mumbai the network is very low at most of the places mainly in slum areas. call drops rate is not so high though. they also offer good schemes for internet and message packs etc but 2G internet speed is so low that it takes around half minute even to load normal google page. so it is okay if u r using aircel as ur secondary sim for low call and message rates but not really good for primary use as will disappointed with network.