This is Thailand. Health insurance here, as a rule, is much cheaper and much simpler than the health insurance most expats are probably used to.
The marketing of all Thai-based health insurance is closely monitored by the Thai government through the Office of Insurance Commission (OIC). The basic policy terms and conditions of most health insurance sold here are pretty much the same, whether sold by AXA, Bupa, LMG Pacific Healthcare, Thai Health Insurance (THI) or other health insurance companies.
What I am referring to are the insurance companies that are actually housed in Thailand and are required to market their product under the rules of Thailand. Bupa is an example.
Bupa is a well known international insurance company. But, they also have offices in Australia, New Zealand, India and many other countries, as well as Thailand. The insurance marketed out of these offices is regulated by the insurance rules of those countries. Therefore, their product may differ in accordance with the rules of the country they are housed in.
Health insurance in Thailand is regulated under two separate sets of rules, rules for health insurance marketed by life insurance companies and rules for health insurance marketed by general insurance companies.
Agents need to pass a separate test to be able to represent either type of insurance company.
Life insurance companies generally market health insurance as a rider to a life insurance policy. Otherwise, health insurance is marketed by health insurance companies as a separate product. As a rule, this form of stand-alone health insurance can provide higher coverage and offer more options for budget shopping. There are some similarities, though. For one thing, you must have an address in Thailand to purchase it.
You can not purchase 100% coverage for daily room & board, you must choose a plan that provides the R & B coverage that you want, or expect to have to pay the difference if you get hospitalized.
If you want a routine check up or get a vaccination, you have to pay for it yourself. For the most part, health insurance in Thailand doesn't provide any kind of "Wellness" benefit.
In terms of general exclusions, you don't need to shop around comparing policy general exclusions. Most health insurance plans in Thailand have the same set of general exclusions.
Also, you don't need to look around for insurance plans that cover medical treatment for motorcycle accidents; they all provide full medical coverage up to the normal limits of the policy you purchase. (That they don't is a popular myth often found in forums).
Health insurance sold in Thailand does not provide coverage for pre-existing conditions. They will exclude coverage for the pre-existing conditions. But will provide coverage for everything else if the pre-existing conditions are not too serious.
Be aware that insurance companies often have difficulty finding competent English speaking staff to deal with their expatriate clientele. Even staff that speak passable English are often hesitant about speaking English with expats.
They often just want to get the process over with as quickly as possible and will just say what they think that you want to hear. This process is called 'greng jai'. It is considered to be a form of politeness in Thailand. In the Western world we know it as "a little white lie."
This is Thailand. Relax and enjoy it.