Credit Cards w/ Chips

Your friend is wrong. Most US banks don't currently offer chip&pin cards. You can still use magnetic strip cards at most all merchants that accept credit cards in Europe. All ATMs accept magnetic strip debit cards as well. The only exceptions you might encounter are at ticket machines, and automatic gas pumps.

It's not a bad idea to know the PIN for at least one of your credit cards, in the unlikely case you have to use it at an ATM to get a cash advance. Of course it's far preferable, not to mention cheaper, to use your debit card at ATM's. The only scenario where you might use a credit card to get cash is if your debit card were lost or stolen. (That's why many people bring a second debit card tied to a different account.) Knowing a credit card PIN simply gives you another layer of backup.

Just returned - only had issues using credit card with the train machines - had to use the ticket counter. Only an issue if you need to purchase a train ticket after hours.

I used my debit card at the machines at the train stations and never had a problem.

We just came back from Belgium and the Netherlands. Our only problems were with gas pumps (Easter holidays, so stations in town were closed). At one station, though, it seemed like we could have used a magnetic strip card if we had also had a 4-digit pin (which, sadly, we did not). So it might be worth knowing just in case. Otherwise, we were able to use the cards just fine, without having a pin.

We had trouble with gas stations (almost ran out of gas but thankfully a local lent us his card and we gave him euros) and restaurants. I would say that 75% of the places we ate our card would not go through.

I think that is more of a problem with your card or card issuer than cards in general. We are not heavy users of a credit card while in Europe but have never had an extended problem beyond an occasional rejection often solved by using another card. We carry three credit cards.