Most guys who are attracted to Thai ladies more than western ones are attracted to the lovely, native, freely natural feminine ways of Thai ladies. The mainstream ones will be loyal, most of them will spend money wisely and prudently, and will be more responsible with maintaining a nice home and helping out with work. Mainstream Thai ladies will not push you to be ambitious but will value "peace, love and harmony" moreso (as most Thais value harmony more than ambition if the latter means conflicts), but they won't have much initiative, as they will tend to seek out a relaxed and peaceful environment with family and friends. It may take a long time before you will find an ambitious and intellectual Thai lady if that's what you're looking for. They are Thai. Nonetheless, they do exist in large numbers here.
If you are fast paced, always moving forward, and expect everything done right the first time, then you're probably headed for frustration with Thai women, and Thais in general. However, if you live a relaxed and peaceful lifestyle, then you'll be at home here.
Exceptions are the "Chinese Thais", specifically those who are 100% of Chinese descent but whose parents were both from immigrant families from China. Most of the offspring of these people are melting pot Thai in disposition, but many are hardworking Chinese. Most of the Chinese who came to Thailand didn't survive from a natural selection viewpoint family-wise, so the current generation of successful immigrant family-descended Chinese Thais have a fairly exceptional subcultural background. You have a wide range or personalities to choose from among the Chinese Thais, but you'll find that a larger percentage of them have ambitions and value education more. Some are a nice blend, the best of both worlds.