I would tend to refer customers to companies instead of ebay sellers. Better support, and typically better products. If you are in the US I would also recommend supporting US vendors. We can't get out of our slump by sending all our disposable income overseas. Just some food for thought...
I honestly feel bad any time I buy something off of ebay that I could buy from a vendor here, so I don't do it very often...probably less than 5% of the time. But sometimes a price is just too good to resist.