Hi am usin reliance sim from 2 year here are my experience.
NETWORK ISSUE : Reliance always having the network issue. if you will move to deeper side in your home then you will lose the network stability.
CUSTOMER SERVICE : Reliance has not that much good in customer service. you have to wait a long time always to give a complaint or request. Some time the executive cut the call or put on hold for a long time with unnecessary reason.
PRICE : Reliance has better price from the all telecom service provider. they have the best postpaid plan always.
INTERNET SPEED : Its depends on the stability of signal if you are getting full signal then it will be the best neither you will hate it.
MERGED WITH OTHER COMPANY : in some state reliance has been merged with other company like aircel due to bad impression. if you are new in that state and having a roaming zone sim then you will face many problem.