Sorry to be negative, but Samui is much changed. Wild horses wouldn't get me there nowadays, unlike a few years ago. Our son has just returned from a business trip to Thai islands(he is in diving insurance). Samui was his least enjoyed destination. Very seedy these days lots of concrete and not unlike Benidorm!! Mind you.....thats what some people like. NOT for me.

A lot of nonsense about Samui as usual.
Maybe you could compare Pattaya with Benidorm.
You could compare Samui with Ibiza in a way.
Same, same but different.
Samui has 1 million visitors a year.
It is not the same as 20 years ago, but most places change.
I'm glad not all the 15 million that visit Thailand go to Samui.

I doubt Samui has as much concrete as here in Phuket. I have only been to Samui one time and stayed at Bophut beach, which was very quiet. Chaweng was not as bad as I had imagined (it can't beat Patong for overblown tourism) and I am sure that if you ride round the island there are loads of quite places just like Phuket - all the tourists stay on a few beaches and leave the rest alone.

Just got back last night from 7 days in Lamai Beach, two years since my last visit. Yes, it has changed; more development and clearly marketing for a more "upscale" crowd but once you get on the beach it all disappears and it becomes the same place you loved. Take a motorbike ride at sunset and there are still nooks and crannies where you can be alone with the beauty of the place.