Beautiful scenery but spoilt by too many visitors

We visited Jiuzhaigou in October. We arrived at the airport mid afternoon and half of our group was immediately troubled by the altitude (3,500metres), suffering headaches, nausea, shortness of breath and dizziness. Then we were driven to the Sheraton in a sardine tin on wheels which made their symptoms even worse. To cap it off the beds at the Sheraton were so hard that nobody got any sleep. As a result half of the group were too ill to even get to see the World Heritage site the next day. Those that did were impressed by the scenery but the day was spoilt by the number of visitors. 40,000 people being ferried up and down the mountain in a day is just too many. Fighting to get on and off the shuttle buses really detracts from the experience. We had lunch in the restaurant which was a mistake because the food was poor quality and the restaurant unhygienic. On top of all that our guide was hopeless! My advice to future visitors would be to allow enough time to acclimatize, avoid the weekends, avoid the restaurant and prepare yourself to fight to get on the shuttle buses.