MTNL here again the victim of Yellow Journalism.
After struggling with BSNL for almost an year, I migrated to Airtel. I was Airtel's first subscriber in our society - in-fact, I was the one who helped them get clearance from our society secretary for trenching their black cables. In your case it's MTNL, in my case it was BSNL. Both orgs function almost in a similar manner. BSNL broadband used to go down ever other day - and would take anything from 6-12 hours to come back up. This was three years ago. Today, still nothing has changed. My friends who live in our society still complain that BSNL goes down every other day. Many people have even claimed that the officers from our exchange have eaten money to the tune of 2cr-4cr (from private players?). I guess this explains why BSNL broadband goes down every other day in our society.
On the other hand, I've been using Airtel broadband since the last 1.5yrs and total downtime during these 1.5yrs must be 6hrs-8hrs at the most. Need I say more? The list goes on...
The thing is that if your local BSNL/MTNL exchange is managed properly and if the officers manning it are not corrupt, you can expect pretty good service. But, in my case, it was the other way round as I have described above. Getting my point?