I had a very good experience with https://www.thestudio.com/ when we needed to order 1,000 pins (total, of 5 designs). Everybody I spoke with was helpful and knowledgable and we got multiple suggestions from their designers and factory for how to make our designs work best in the medium. I'd definitely use them again, and I'd go as far as requesting to work with the same sales, support and service people.

I'm not used to dealing with vendors, but I thought that their sales team was very high pressure. That said, I had a hard budget (which was drastically below their asking price) and they worked with me to find a price that suited.