I've not had problems with my Diners (MasterCard branded) chip and PIN card at automated kiosks nor my MasterCard Citi Executive (EMV chip but signature only) at staffed locations or online.
Online is often cheaper - use tgv-europe.com, never
www.raileurope.com - as you get the benefits of discounts for advance purchase, loisir, etc. For TGV / Eurostar, you can print out tickets; for TER etc. you have to use a chip and PIN card and retrieve the card at an automated kiosk.
I will ask the moderator to place this in the European Rail Travel forum.