There has always been a number of questions regarding which Thai embassies expats normally use in and around Asia. These are the embassies which most expats and foreigners use in Thailand with a note of their Thai visa process times and what they normally will and will not issue being a bit about the embassy procedures. Note that this was correct at the time of writing and that timelines and procedures do change over time.
Considering visiting Thailand then consider obtaining a tourist visa for Thailand instead of risking your holiday with a visa on arrival. The visa laws have changed over the last few years as the government attempt to cut down on visa abuse where people lived in Thailand on back-to-back tourist visas. These are the basics for the tourist visa.