My wife and I stayed there for 3 nights this year in march. It's a very nice hotel in a beautiful landscape. And yes it's far outside of Chiang Mai, so a motobike or even better a rental car is needed if you don't want to stay inside the hotel all the time.

I'm a Platinum Member myself, but I can't tell you anything about possible upgrade, because we booked a Jacuzzi Pavillion through a german tour operator. This way it was much cheaper then through accorhotels.com or the hotel website.

Here are some videos from our stay:

http://www.youtube.com/watch?v=Pwu-tsEuF_k

http://www.youtube.com/watch?v=8TJYF2mdMmQ

http://www.youtube.com/watch?v=cYZHXyVeUrY