It's very dependent on how you book and your status level. When booking, I've always found an E+ seat, but that's because I'm more likely to choose a flight with good seat availability, I usually purchase at least a couple of weeks in advance, and I have flexibility with travel dates/times. It's quite easy to imagine being an elite and getting stuck in E- because the flight was just about full (just ask PTravel ) - trying to get seats on short notice out of a hub generally puts you at the back of the bus.

As for standby, I've definitely been in E- at least once before. I lucked out and got an empty row, but that was because of misconnects.