I use a 3g internet dongle in Pune. No problems whatsoever with connectivity or speed. Speed does tend to go down during the weekends. However, you won’t feel it unless you are watching streaming videos.
If you read most reviews, you will see that most brick-bats are for customer support. Best way to avoid them is to go in for pre-paid, so you get what you pay for. Unlike in postpaid where you get a surprise with unknown/ vague charges at the end of the month.
Signal strength may go down in some areas if you lock yourself up in the innermost bedroom. But this is a problem with all operators.