Right now the only CURRENT Omega model I would consider buying is the Speedy Pro, though I'm looking at vintage versions as well. I have nothing against the Planet Ocean, but I think the Speedy Pro gives you more "bang for the buck". It has a better movement, it retails for $400 less than the PO, it has a chronograph function, and it has a proven track record of reliability and durability. I think the Lemania movement used in this watch is the best movement in the Omega catalog, and I doubt you'll find many people who will disagree with that. It has the longest track record of any Omega movement, and the watch itself has been around for decades with only minor changes over the years. This makes it an absolute timeless classic.
Hesalite vs. sapphire is a personal decision. You pay an extra $780 for the sapphire sandwich (crystal and caseback), so if you really love to see your watch's movement at work and you are prone to bumping your crystal into things, then you'll probably want this model (3573.50.00). Otherwise, the hesalite can easily be polished to remove scratches.
One thing to keep in mind regarding the co-axial escapement in the Planet Ocean is that it may not reduce servicing intervals the way Omega originally claimed. At first they claimed a co-axial could go 10 years between servicings, then they reduced it to 8, and in my last e-mail to them they responded with 6-8. In a later e-mail another person was told 4-6, depending on usage. So, there's a chance that co-axial watches will require servicing just as often as watches with traditional escapements. I suspect this is because the co-axial escapement itself requires very little lubrication and can go a long time between servicings, but it is still connected to a modified ETA movement that still requires regular servicing. Until we have more real-world data, we can't say for sure how long a co-axial can really go between servicings.
Good luck with your decision,
John
