Just FYI...It is "co-axial", not "co-axle". I posted some of this in an earlier post, but the co-axial movement is Omega's own in-house movement. The movement allows for less friction between parts, which supposedly makes the watch operate more efficiently and thus allows for greater long term accuracy. It also requires less frequent servicing. Other Omega movements are heavily modified ETA movements, so they can be sold at a lower price. I own 2 SMP 300M watches, a Swatch quartz watch, and a DeVille co-axial. Of all of these watches, only the DeVille virtually never needs to be reset. I may have just been lucky and received an exceptionally accurate watch, but its performance so far has definitely sold me on the co-axial movement.
The exact pricing of the Planet Ocean models has not yet been announced for the US market, but the extra cost can be attributed to twice the depth rating (600M vs. 300M) and the co-axial movement. I'm waiting for the prices to officially be released and to see one in person before I decide if it is worth the money.
Do keep in mind that you can get at least 30% off the retail price from deep discounting authorized retailers.