As a Delta Platinum, I wasn't sure if I was going to be able to "upgrade" to EC without paying, but I had a very friendly check-in agent and she changed my seat with no problem. I was in the last row (17) of EC on the 747-Combi and I have to say it was relatively comfortable. The service was exactly the same as regular coach, but the EC mini-cabin did have a much better feel to it (not to mention that it was only half full so I had my own row). The only problem I found with the last row was that the armrests didn't go up all the way, so I was rather uncomfortable when I tried to sleep on the 3 seats, but then again, that is a bonus, not a right on a trans-atlantic flight. (PTV's were already installed and the seatbacks weren't really a problem even when they were fully reclined)

I'm returing to IAH tomorrow and I was "automatically" put into EC on the way back, so I didn't even have to deal with agents in ZRH or AMS. The only bad side is that it looks like the whole plane is full, so won't have as much room to stretch out as the outgoing flight. That being said, I'd much rather have the 35" than the 31" on a trans-atlantic flight.