This question has been asked hundreds of times. There is no true answer.
All you're going to get is opinions. Those who were happy with their purchase will say their vendor is the best. Those who had a bad experience will tell you not to buy from whoever they did. The engine kits from China are all about the same. What you should be concerned with is after sale/ customer support. Price and shipping fees also come into play. Do some reading and research. http://www.google.com/cse?cx=partner...kit&gsc.page=1