Using credit cards while traveling

If you had both a US and a UK credit card, which would you use in Europe or anywhere that uses euros?  I'm not sure...I suppose I should look up the terms for both.  I'm thinking the UK card as they have chip and pin over in Europe.   Any thoughts?

I would check Which company has the lower commission. IE the company I work for charges an addl. 2.99% on your overseas spend. And a few other notes:

1. Always notify your provider your traveling

2. Always have a backup, and some sort of access to cash

3. Always check the fronts of any ATMs you use abroad for any suspicious addons, cameras, or false front plates. cover you hand when you type your pin as ATMs in tourist areas have a higher percentage of fraud activity.

4. If your credit card has a cash facility, activate it.

If commissions are the same, I would recommend the UK card for chip and pin reasons.