I have a long story to tell you, on my personal experience.
My Mom and Dad visited us Sept 2002 and were staying at my sister's house. My Mom had some breathlessness and we took her to emergency. (She had insurance from here) They did all the relevant tests, and realised she had 3 blocks of almost 99 % in heart. Doctors suggested not to fly to India with this condition. So we spoke to agent and he said that they have coverage of 50,000 $s. The doctors said that they will help us to reduce the expenses. So expected the total expenses around 60,000 $s. After operating her, she expired the same day when she got discharge from hospital. The doctors hurried to discharge her. in spite of the fact that she was not breathing properly.
Now the harrasement from Insurance company started. They said that she had the heart condition pre-existing and they are not going to pay. We got all the relevant letters from the doctors whom my Mom visited. The bill was almost 75,000 $s. They went back and forth and said that they spoke to our cardiologist in India and he said that my Mom had prexisting condition. So we spoke to doctor and he said that he never spoke to anyone. Afterwards, we sent a lawyer's notice, along with cc to Insurance commisioner.
Finally they have released 50,000 $s. My Dad had signed her emergency papers, so the lawyer said that we need not pay anything and he sent a letter on my Dad's behalf that he is not capable of paying that amount.
Anyway, the morale of the story is buy insurance from here only. Since Indian based insurance you have to pay first and then they reimburse which is very risky.
I have one more friend whose father had heart attack, last week and he has insurance from India. The total bill is 40,000. I will send details of what is final outcome.