Well, this like all "should I upgrade" questions is largely subjective. The answer depends on how many miles you have, how many e-500's you have, when they expire, what you look for in an upgrade, whether or not you need to sleep on the flight/get work done, etc.

Meal service on this flight is just the fruit & cheese flight, so that is something to think about, too. For me, if I had a meeting the next day, and it looked like Y was full, I'd go for the upgrade, but that's just me. You'd have to decide what and why its important for you.