Have used both those to ship parts down here, plus Heartbeat City (HBC), D&R, NPD, Firewheel Classics and more. HBC in particular has good parts, although a little pricey, but they do offer 'Made in USA' quality parts as well as the cheaper Taiwan/ROC repros. I've generally found parts made by CHQ to be very nice.
There used to be rumours that some vendors sent previously-returned parts overseas to get rid of them out of stock, knowing nobody would pay for returns outside of North America, but I've bought thousands of $ of parts over the years and never experienced that issue.
Best to contact the vendor first with specific questions if you have particular expectations though, since quality, fit and finish do not always correlate well with price. Also watch out for the GST threshhold, as it can be cheaper to place several orders rather than one; also allows you to see how a vendor performs before placing another order.