It was amazing! I was there for my sister's wedding (her husband's family is Thai) so it wasn't a totally normal experience, but it was truly a wonderful trip and I can't wait to go back!
We did several days in Bangkok and then went to the town where her in laws live (which isn't a tourist area) and then the rest of the group went to Phuket (sadly I had to head home)
We stayed at The Peninsula in Bangkok - it was just breathtaking. Hands down the nicest hotel I've ever stayed in. The breakfast there was unbelievable. It's right on the river and the staff was over the top helpful and gracious. (To the point where, supposedly, they adjust the arrival a/c in the room based upon the guests country of origin. Americans like their rooms cold, evidently. You can obviously adjust it yourself as well.)
The temples, the ruins, the food. So much good stuff.