Need recommendations for a great internationa/data Sim card

Can any of you seasoned European travelers give me a recommendation for a good data/sim card?  I was going to buy one from Telestial but the reviews on Amazon are beyond horrible so I guess I won't use that one.  I would rather have one card with the same number as we will be in quite a few countries. I know it's cheaper to buy them as you enter the country, but I prefer the convenience of having it all set up before we leave.

Help!  (and thanks)