I live in India, and I happened to somehow end up in a place where there is only one choice for Internet connection - BSNL. As much as I would have preferred Airtel, since I have already experienced and loved their quality of service, I have to put up with BSNL. What is wrong with BSNL? I suppose I can summarize the service in one sentence - it's a government service. Among other things, the waiting time is 20 mins, and over 95% of time the reps will be unable to solve the problem after taking you through the routine of checking all the modem options and finally reconfiguring the modem.
Worst of all, they don't support any other modems or routers than those BSNL provides - and that's put flat on the initial contract statement itself. However, I required an wireless modem. Despite my lack of faith on the quality of the modem that they'd provide, I chose to get it from them since they will at-least 'support' that device. But they did not have one in stock. Apparently they were out of stock and remained out of stock for a full month that I bothered to inquire. Then I thought I've had enough - and went out to buy a separate router.
However, I also have got a basic BSNL's modem by then, made by a company called UT Starcom. The modem stopped identifying the Ethernet connection after 2 months of use. The company's site is as good as BSNL's, so if you have a question about it it's better to call up BSNL guys. They could not do anything - but that doesn't matter to me much, as I use the NetGear modem instead. But I'd advise you to get a BSNL modem in rent, because when they mess up something, and the net doesn't work, and even if it is obvious for a 10 year that it is their connection at fault and not the modem configuration - they will refuse to help you unless you are able to tell them what you see in the router's diagnostic pages they ask you to go to. And they won't cooperate if you ask them what information they want so that you can get it from your non-BSNL modem.
Hence it is advisable to steer clear of BSNL, if your budget and location allows it. I'd suggest Airtel as it provides similar plans on similar price range, but far superior service quality.