Alan,
Why are you so hung up on whether the Mark 16 uses an in-house movement or an ETA?
and what leads to you into believing that the Omega 8500 calibre is a "much better" movement than the ETA? Most of Omega so-called in-house movements are in fact based on the ETA movements (and replaced their escapement with their famous "co-axial escapement"). The benefits of Omega's co-axial escapement, I believe, is reducing some friction amongst the gears, thereby not requiring as frequent "regular services" as their ETA counterpart. However, you must realize that even a regular ETA doesn't necessarily require servicing in a few years (maybe 5). Furthermore, a lot of "regular services" do more than lubrication, but other fixes too... which... the co-axial escapement doesn't help alleviate.
Also, the ETA 289x movement is simply one of the best in its category. You will find that in most brand of watches, their COSC grade watches are all using this ETA 289x series of movements. Why? because it was a well-designed movement to begin with... that's why Swatch group adopted it as a defacto standard for many of their watches, and used it to save Swiss watch-making industry and fought a good battle against the uprising of quartz watches from Asia.
I am in the IT industry myself... so pardon me for a poor analogy. It is very poor, so please beware. Intel is not known for making the most elegant micro-processors. Yet, its 80x86 architecture (despite having some idiosyncrasies which are not preferred by many) is robust, well-suppported, and widely-adopted. Yes, at one point every computer company manufactures its own advanced CPUs... but ultimately, if you want lots of raw-power that is affordable, and allow you to run mainstream applications, which would you choose? SPARC/PA-RISC/Itanium/POWER? Intel 80x86, of course! (and there is always an AMD/Sellita.. but let's forget them for now).
Apple was once very proud of its (Motorola/Apple/IBM's) PowerPC. Looks what it puts in its Mac nowadays? Intel CPUs! are these Intel CPUs soul-less, cheaply available from Dell/Gateway? sure. However, when they power-up the Macs, they manage to keep Mac running elegantly. Do people nowadays care that their Macs don't run on PowerPC but Intel 80x86? probably not.
By the same token... yes, surely we appreciate IWC producing their own movements. However, when economy-of-scale is of concerned, IWC using ETA movements could keep their "lowerend" watches affordable. Would you consider the Mark 16 if it costs 50% more than it does now? at least IWC gives us a choice. If you want nice yet functional (and relatively affordable) "lowerend" IWCs, you could get the ones with ETA movements; if you want in-house movements, you could get the "higher-end" ones. Will the "higher-end" ones necessarily be more accurate than the ETA ones? hrmm... up to you to decide.
In summary, pardon me for my poor analogy--but allow me to say this (in my opinion): an ETA movement doesn't make IWC an inferior product, it makes it more affordable to mortals like me. Apple Macs are more expensive than a similarly configured Dell... but there are those would be very eager to shell out more for an Apple than a Dell for whatever reasons. The question is... does it suit you needs and wants?
