I have talked to many TGs. They are diverse in their opinions as most women everywhere.
Ones who tell me they like Thai men say they have heart broken too many times from farangs whom come and go, never see them again or next time with different girl. Also, because Thai men speak the same language, they know how to make jokes, get TGs to laugh, and whisper sweet nothings in their ears. Some say Thai men are better lovers, I think mostly because of language, things they have in common, and understanding of TGs attitudes about love and sex.
Ones who like farangs better, many times are divorced and had bad experience with ex-husband or BF, who treated them bad, ran around w/ other women, physically abusive or ran out on them after birth of child. There are some who find farangs more physically attractive, mainly because of white skin, also blue and green eyes, light-colored hair. Among the Thai, people with whiter skin are considered more high-class, and Thais are very, very class conscious. Also, in any country, some women will find foreigners attractive because they aer different and exotic to them. Also, I suspect that watching movies where the heroes are usually farang has an effect on some. Still, all in all, I think that most TGs find Thai men more attractive, because farangs seem strange-looking, very, very much more hairy than Thais, and smell different than the men they grew up loving(fathers, brothers, etc.)
Having said that, next to power, money is the greatest aphrodisiac, and it overrides all other concerns and preferences to a great extent, especially when you are dealing with BGs. Even non-bar TGs are very impressed with money and like to be wined and dined and treated in a classy way. They are impressed when farangs spend money, with seemingly no concern for the amount of the bill. To us it is little. To them it is great. Most women anywhere are impressed when treated this way. Also the prospect of marrying a man w/ money is very attractive to them, as well.
However, while w/ most BGs, while age is not much of a factor, it is w/ many(but not all) TGs, because they are afraid if their friends, acquaintences see them w/ much older farang, then they will think that they are maybe engaged in prostitution. But if a girl has a spotless reputation, and doesn't care what others think, then it is no problem.