I have two hard data points RE: card acceptance for the PenFed 'chip enabled' Visa card. This card supports a PIN, but defaults to signature verification. Last month the card was rejected by the automated tollbooth in France (near Carcassonne), despite the PIN verification option on the card. Today in the SPAR market in Rhayader, Wales the cashier invalidated the transaction because the card negotiated signature verification. She said they don't allow signature verification, only PINs.
FWIW, I have never been prompted for the PIN on this card. Whenever I have used it, it has always negotiated signature verification (even at the self-service supermarket checkout lanes). However, I am also carrying an SDFCU 'EMV Visa', and I can confirm it worked w/PIN in the automated ticket machines in the Madrid metro. However, it has always negotiated signature verification as well every other time I have used it.