I am a vodafone customer for the last 4 years. I have not faced any type of problem regarding network. hence I would surely vouch for its network stability. But the major concern is the aftersales service. neither you get any sort of promotional information nor the customer care people are professional. Most of the executive are unable to answer your queries in proper manner.
Vodafone is not coming up with growing ideas like other competitive service providers. The main contender of vodafone is providing the Mobile internet scheme in 98 rs where as you get it from vodafone with a minimum of 198 rs. You will never have a proper response regarding this from the customer support.
Anyways, I am happy with the network but not with the offers and service.