I checked around and there still appear to be a number of ADs who are selling that model with a movement denoted "2500", which I inferred to mean a movement that was in that piece before Omega made a (recent) decision to offer the Aqua Terra with its in-house 8500 movement. Which, in turn, means that for now, it might prove to be difficult to locate the Aqua Terra with the 8500 (that is, until the inventory of older pieces clears the market). In any event, I'm absolutely smitten with the Planet Ocean and don't think the watch (coaxial, with the ETA 2892-2) is exactly chopped liver. So I prefer to keep what I have and wait till Omega gets around to putting the 8500 in that model. I'd rather do that than spring for a Milgauss. I did some reading on the 8500 movement (thanks to your discussing it, I might add...) and it strikes me as a horological tour de force -- one suggests that getting a Milgauss instead might even be a downward trade.