I absolutely love ordering from Chinese suppliers, 90% of my orders have came from there.
Purchased from ruyandirect and eastmall multiple times. Eastmall's replacing a few parts I had fail free of charge due to their no-hassle warranty.

Dear US suppliers, I do not plan to order from you unless you have similar prices. $10 for a case I can get from Wayne for $3.50? kthxbai.
I don't want to get off topic(since this thread is geared toward Chinese suppliers), but there are some advantages to purchasing from US suppliers. There's definitely less shipping time, most orders I've made with US suppliers have taken less than 4 days(often 3 days). I'm sure if there's a dispute with a failed product, it can take less time & money to replace.
While some US suppliers do charge more than most Chinese suppliers, I think they have to account for the cost of acquiring the items. You have to keep in mind that they're also looking to make a profit, but having to ship the item to themselves via China can be somewhat costly as well. Not to mention defects, seized items, warranties, etc...
"Sar" made a pretty good point that some deals are indeed better state side. So if costs are what your looking for, you should still consider comparing prices states side & overseas to see where you can get the best deals.
For me personally, I've ordered from these US suppliers and they've been fast & efficient in terms of getting the items to me.
Dietsmokes, TotallyWicked, eSmokershop, DigitalCigs, and a few others. All orders were received promptly & in working condition.