Pros: Cash back. Did work exactly ONCE in China.
Cons: Low acceptance rate overseas, incl. China. Does not accept collect calls.
Don't rely on Discover Card for overseas use.
Discover Card announced the removal of Foreign Transaction Fees on Oct 20, 2011.
I did manage to use the card exactly only once---to pay for a hotel stay in China.
Discover Card does offer a "notice to vendors", in both Chinese and English, informing merchants to process the card on UnionPay terminals and not demand for a PIN.
I tried to pay for another hotel stay two days later. No dice---"card declined". Tried paying for tickets at the Temple for the Heavens, same thing---even though both the UnionPay and the Discover logos were on display at the ticket counter.
Meanwhile, not a single notice from Discover.
No email or voicemail; I log all voicemail and missed calls by Google Voice.
Lo and behold, when I logged onto DiscoverCard.com a week later to catch up with my bills stateside, my online access had been blocked. While I could read the Secure Messages, I could not send any message. There's no notice about "suspicious activities" etc. And unlike Amex, Discover does not accept collect calls.
Bottom-line: keep your Discover Cards at home. Count yourself lucky if you can use it at all. Obviously they have no mechanism in place to help when your card gets declined overseas.