I've owned both.
For city driving in heavy traffic automatics are less tiring. But if you live in the provinces manuals are fine. Manuals have come a long way in 53 years. Gone are the heavy , tiring clutches of the past. Now very slick and smooth so no difficulty changing gears.
However, Thai women being generally shorter might find reaching the pedals more difficult and prefer autos.
I would even be prepared to pay more for a manual as I like their versatility.
Each to his own as someone has said.