Telenor earlier known as uninor was very popular in providing cheap price service
Pros:-
1) The call rates are really very less expensive as well the SMS charges
2) It now also provides 4G services at a very reasonable low price.
Cons:-
1) The voice call quality are just worst as u never get clear quality
2) Most of the time you will get error of busy network
3) The 4G network is cheap but believe me it is worst, it is even slower than 2G.
4) The network coverage is really bad in rural areas