I generally avoid commenting on suppliers that haven't been around long or who I haven't done any business with, so take this with the appropriate grains of salt... One thing I've learned running this forum for the past 2 years and my time before that trying to find reliable and reputable suppliers is that most of them start out very eager to please early on, so there is usually a little less risk sourcing from a supplier that's trying to build a good reputation compared to one that's been established and can become a little lazy or less focused on customer satisfaction. That's not to say some vendors haven't been complete failures from the start (DongDu, Hebei Lianfu, and Henan Tengmao immediately come to mind), but I think overall it's probably not terribly risky to make a small purchase from a new vendor to gauge their potential for larger and more frequent orders.
Always remember when sourcing in this hobby that there is never zero risk, and I think it's best for most people to assume and prepare for an eventual screwing. Eyes wide open and all.