Help me to choose between smp and po

Exactly—in which case the more extravagantly overengineered watch would be the one that would make the user happier. Don’t get me wrong: it’s cool that Omega can mass produce watches with ludicrous specs like that. I only meant that choosing one ref over another because the movement is “better” might not be the best move. Unless the “better” spec in question is something you have some particular interest in (from a geeky standpoint), it’s unlikely to be a meaningful difference for a day-to-day wearer.

The only ways the 8900 is "better" is because of an extra five hour reserve and a slightly higher tolerance of +5 as opposed to the 8800 which has +6 because it is a smaller movement. Other than these, there is no difference in quality.

Sure, though which modern luxury mechanical movement (or watch) isn't "extravagantly over engineered"?

To clarify, this is all just expensive, luxury men's jewelry purchased for purely emotional reasons, so adjectives like "ludicrous" & "geeky" apply to all of us for everything, right?

Some of us like ludicrous this & others, ludicrous that.

For example we could all agree that precious metals on a dive watch are ludicrous & extravagantly over engineered ... But we probably wouldn't 😀

Love the PO, but found it a chore to wear at the 43mm size. I own and wear dive with several larger watches but IMO -- and this is heresy -- I never got a fit that wasn't either top-heavy or unstable on bracelet to strap, and ended up selling mine and picking up a classic Marinemaster, which lacks some of the jazz but has been rock-solid and more wearable for me. Haven't tried the 39.5 but it has a dedicated following.

The SMP is the easier choice as an everyday dressy diver in my limited experience. It's very dynamic, with its many surfaces and textures, but still retains its legibility in most variants. Wears fine for most on the (IMO clunky) bracelet and beautifully on a strap, and there are quite a few good aftermarket ones now that approach the OEM for comfort and build quality.

I prefer the Heritage over either of the others, but that's as much about fit as anything else, and I use an SMP as my work watch so it gets a lot of wrist time. Classic and highly distinctive case and bezel and beautiful dials against a somewhat polarizing handset, HEV, bracelet and bezel, but overall one of the great modern divers, even at its current price point. I've had better and more consistent accuracy from the 8900s I've owned but that's pretty much much luck of the draw I expect. The 8900 is prettier, if that matters.

Can't go wrong with either -- this seems a heart over head decision. Bon chance.