My husband & I flew round trip to Zurich back in June on Delta. We debated over whether to pay extra for EC seating(well he didn't have to pay because of his status with Delta)but we ended up paying the extra for me. I'm short like you & hubby is 6 foot so he always gets an EC seat if possible. Boy was I happy that we coughed up the extra money! It was well worth it for such a long flight so I highly recommend it! Have a great trip!!

Thanks!

On DL178 and DL179 between PDX-AMS, Delta uses 3 types of planes depending on your departure dates. Knowing exactly which plane model uses helps you find seats with more leg room than ordinary EC seats. Use www.seatguru.com to look up precisely which plane model you are looking at.
On A330-200, 10AB,CG, HJ have significantly more leg room than other EC so that you can even move in/out of the window seat without asking the aisle seat person to move. 11CG also don't have front seat, but your leg is exposed to people and carts passing by. The overhead bins on this plane are not cluttered with oxygen bottles.
On B767-300ER, 17ABCDE have enormous leg rooms, perhaps even more than the business class. Although the seatguru says 16FG are ordinary seats, aside from closeness to the bathroom, it also had a lot of leg room. The overhead bins over these mentioned seats are pretty much useless on this plane as it is packed with oxygen bottles.
On A330-300, 10AJ are problem seats even though there are no seats in front. The part of the door is sticking into your leg room. Look at http://www.modhop.com/delta-airlines-airbus-a330-300-economy-seat-10a-exit-row/

I just upgraded us to Economy plus on delta for a Atlanta to Zurich and Zurich to Jfk routes! I am glad to hear that it is worth a few extra bucks. I am the shortest at 5'6 in my family! DH is 6'2 and both DDs are 5'9. That is what sold me.