Keep the Oly 17mm 1.8 or the Panasonic 20mm 1.7?

Sure, he's free to return it, but I think it's legitimate to be concerned when people are buying and returning items so frequently (not the OP so much as many others out there). This increases costs for the manufacturers and retailers, and that added cost is passed along to us. Most times that a lens goes from new to refurbished, it costs hundreds of dollars to ship back, inspect, repack, reship, and sell at a discount.

Who knows, every time someone returns a perfectly good lens, it could add a few cents to the cost of your next purchase.