I am using Vodafone network and its internet services. recently I have been to manali for trekking and even in dense forest areas my vodafone network was working fairly. interney speed was ok ok but the telephone network was far better than other telecom compnies.
at the top peaks signal was excellent. in the deep down areas network was not effective but in normal peaks and hight peaks it was really good. I could connect to my parents from that area.