Bsnl 3g have very bad network and this operator gives very cheap net packs but the net is very slow, so this makes bsnl 3g a bad service provider, this operator have a not so good customer service, if you call them once they will not receive your calls.
They have cheaper net packs but what you can do if the net is slow you can not download and upload anything in high speed they have only upto 128 kbps speed