How unacceptable are the American magnetic strip credit/debit cards? I didn't have any trouble 3 years ago, but I hear that things have changed.
Not much has changed. Any merchant that deals with tourists on a regular basis has the hardware to read magnetic cards. The only problem is at ticket machines in train stations.
No problems. The only exceptions are in automated ticket machines and unattended gas stations. Everywhere else they are fine.
In the interest of a complete response, there have been a few posts here stating that some out-of-the way shops in some places no longer take the non-chip & pin credit cards. Also, I think there was a post saying they weren't being accepted in an entire country (was it Denmark? I don't recall). So although the responses you've received so far are mostly correct, there is some indication that this may not be as universally true as it was 3 years ago. Stores are supposed to accept the magnetic strip credit cards according to our understanding of the rules of VISA and Master Card, for what it is worth. I think the consensus is that ATMs still work just fine with non-chip & pin debit cards. Therefore, the conventional advice is just get cash and pay for everything that way.
There ARE certain stores and businesses that won't accept US-type credit cards, but as the last poster noted, they're not businesses a typical tourist would likely visit. Ikea and Media Markt are two of the more well-known examples, but really, who on this website goes to Europe to buy a plasma TV or a Poång?
who on this website goes to Europe to buy a plasma TV I do!! Media Markt rocks!!! I always save money over the UK.