We first went to Thailand about 20 years ago about 3/4 times, when Phuket was little more than a few restaurants. It was literally paradise on earth. Fast forward 10 years and it had become very commercialised. We returned 5 years ago and counted the hours till we left.
The constant selling was relentless. The minute we stepped out of the hotel, people touted for business. You want tuk tuk?, you come to my restaurant? We got a taxi to Phuket town one day, and getting out of the car, were approached by three other drivers asking if we wanted a taxi. You could not relax on the beach. There would be sellers every three minutes who would disturb you, despite you reading a book or listening through headphones.
The sex trade is in your face, and fairly disturbing. Even more disturbing that the Thai Government do little to stop it. All those 16 year old Thai girls are on sitting on the laps of 60 year old men all day because they fancy them. Countless times when my DH was sitting in a bar waiting for me to arrive, he would be offered sex, or 'overnight lady friend' . We were sitting watching a sunset one evening and two girls came up to us, and started chatting, told us they were learning English. Within 5 minutes they were offering to go to bed with us. Yuk. Lovely way to ruin the sunset.
I have been to very many countries, and lived in a few. Thailand, and Coffs Harbour, Australia - I would not go to if you paid me.
Malaysia on the other hand is lovely. Kuala Lumpur is my favourite city on earth. Such contrasts the affluent, little India, China town.
When you book flights , seriously consider Emirates. They are fantastic with kids, and you have a 30kg luggage allowance!