Just to muddy the waters a bit more. Another factor is what the company is like at actually paying out.
A mate who is senior in an Australian Hospital group says the one they have least trouble with is Covermore. Because I go to Thailand a fair bit, I asked a mate at the Royal Bangkok hospital. He said they had no trouble with any of the Australian based insurers.
Travel insurance is dramatically cheaper via the web than via travel agents, etc. I have an annual multi trip policy with QBE, primarily because it was one of the cheapest.