If there is a third choice, i choose koh samet. For beach it more beautiful and for tourist it less crowded.
2nd choice hua hin, went before 4 yes back. Some part of the beach they have wall or fence to block off wave in case big storm.not sure whether they took it down or not.so so beach, but if you like to visit temple there is the largest Luang poo tuad temple called WAT HUAY MONKOL.
Pattaya- infested with all kinds of farangs around the world. Sleezy place with agogo bars, gay bars.beach so so.thai tourism board earlier on try to clean up the image of pattaya but seem unsucessful.
Some of the days you can notice an increased of homeless farangs along the beach area where they have lost everything to their thai gf or wives after breakup. They have no more to go back home.