Incredible views that brings a tear to any eye seeing it.
Looks different from the various seasons. Make sure you stay a night in the town, just to experience the local culture. Trust me, this is far from Thailand. Culture here is mountain-style.
Great hospitality, but I guess that's because of the tourist dollars that enters this part of the world. But hey, travelling this far, a few more bahts won't hurt. You should spend money wisely though. Forget about the handicrafts. There are better quality ones that's sent to the bigger cities like Chiang Rai and Chiang Mai. I'm sure the villages make handicrafts for sale at the major cities. The ones I saw were of poorer quality, unfortunately.
Spend money on food. Especially when it takes some effort for the locals to prepare it and serve it. At least they get work to do. Tip if you can. It goes a long way. They have many children.
Spend money accommodation. Nothing's worse than operating a quiet resort, hotel. Almost every establishment there offers some kind of view, stunning or fantastic. Go with instinct. The prices shouldn't vary too much since it is an easy walk to the next hotel, resort.
Best if you drive up yourself. Forget the tour buses. Take your time, get lost, soak in the weather, the view, the people, talk to them. It's a worthwhile experience.
I was there in January. Tail-end of the winter season, but still damn bloody cold (for my Asian standards). We booked a room, but it was tiny, so we pitched a tent. It was really nice to be out in the tent... even though chilling cold.