I've been on Koh Samet twice, and each time, i stayed at comfy, cozy, quiet places. So, I kinda like it. But I did not like the busy beaches with the large resorts, or the chaotic little town right near the north pier.
I even found a little paradise .... believe it or not ... on Phuket. I never had any desire to go to that island, but when I lived in Singapore, I had a 4-day weekend and wanted a quick trip. I could fly to Phuket after finishing work in the eve, then, after 4 longs day, fly back to SG late at night.
I did a bit of research, and found a virtually deserted beach at the end of a cul-de-sac behind Nai Harn. A place called Ao Sane beach. Very peaceful. One rustic but comfy guesthouse on that beach, and another upscale resort.
Much of the rest of Phuket is kinda like a city ... horrible.
The only island in Thailand that i did not really like was Koh Sichang, just north of Pattaya. A bit rural, but no attractive beaches.
No I wasn't a big fan of the busy beaches either. The resorts were fine, but the island itself wasn't as amazing compared to all the other ones.
I also went at a time when the weather was not ideal so that probably didn't play in its favour.
Thanks for the tips on Ao Sane. I'll keep that in mind for myself and others who often ask for tips on Thailand. I must admit Phuket is usually just a transit town for me.