I went to China for 4 month starting early December and I was back early April on business assignment. I was originally scheduled for two months but one thing lead to another and I was there for four months. I wouldn't say that it was all nice and smooth trip, in fact it was quite challenging due to not being able to speak the language (despite my appearance and being Chinese myself). I had culture shock and homesick for the first month I was there, but fortunately, everything seemed easier after.
It is good to be back :)