I have been to all the cities you mention and could not wait to get back to korat. But people will always say the city they live in is the best and for them like me it is, so try them all meet other westerners and try all the restaurants etc etc. I meet many English, Aussies and a few other nationalities in one of the three large shopping malls we have here and also have friends who dont like to meet that way, preffering to meet at home or restaurant. I am English and if you decide to visit Korat DM me and we will meet up for a pint/coffee/tea.