I havent been using VSNL for long. But I am a very regular surfer. I stay in mumbai. I tried the MTNL 24880000 line which takes your telephone number as userid. I must say that I havent connected to the server with less than 2 calls. Each time I have to dial atleast 2 times. Speeds are pathetic in peak time.
VSNL on the other hand gave a good connection. You get connected in the first call itself even in peak hours. No disconnection even in the event of another call coming. Steady download speed of 5k per second. I feel this speed is because of my 56k modem. One of my friends has a 33.6k modem and he gets download speed of 3-3.5k.
So, all in all, VSNL can be branded as the best ISPs. But not all is goody-goody. I tried purchasing the account online and it errored out. So my only option was to contact a VSNL retailer and purchase an account from him. But from then on I havent had any kind of problem. So for those who are willing to take pains for only one time, VSNL seems to be it.