I also have purchased from Swallowtail and Diane's, I first met her on the Hog Wild Seed Swap. She is very nice.
Before I came to ATP I loved to shop for seeds on eBay. I had a bad experience with a hosta purchase which made me rethink purchasing plants or seeds from eBay. For one thing, by the time they bloom your buyer protection will be expired. So if you shop on eBay try to get a real email address from the seller because you will not be able to contact them at all if your transaction number is expired and it will expire in 90 days. After 90 days there will be no trace of a transaction. I still order from the people I know.