Here is a shocking comparison... I had my appendix removed at a private hospital in the Chonburi area. The cost was 140,000 Baht (6 nights in hospital and a Cat Scan; the latter I deem totally unnecessary) AND THAT WAS 12 YEARS AGO!! When I presented to the doctor with great pain in lower right trunk, she didn't know what my ailment was! I had to suggest appendicitis.
Even my insurance agent was shocked at the high price. Happily, however, the insurance company paid the bill up front. I did not have to file a claim later.
So, I agree, better to go to a government hospital.