If you would like to send me the watch, I am willing to do an objective side by side comparison of it and a modern Omega, and post the results here. PM me and we can work out the details. I'll include real timing data, photos of the movements, pressure testing, case details - the whole works.
Oh, and I've handled and serviced many Seiko watches of varying quality, including Grand Seikos.
Well, given what I have seen of the watch from what you posted, I doubt it would match a PO based on my earlier comparison. I can't speak for the Black Bay.
This is an interesting bit of information for those who are not aware, but in reality doesn't have a lot to do with the objective quality. Timex pin-lever movements were all "in-house" as well, and although rugged no one would call them pretty or terribly accurate.
I don't know of a Grand Seiko that can be had new for $1500 - please let me know what model you are specifically referring to thanks.
Seiko technology for high beat movements is nothing different to high beat movement from other makers, like Zenith for example. The Spring Drive being a quartz watch, that is a whole other conversation, but yes it's unusual in the way it's been done.
The watch you have is a nice watch certainly, but I think saying it is the equal of watches costing many times the amount this does is a disservice to the Seiko. It stands on it's own merits and really doesn't need the sort of hyperbole that is often seen on forums.
Cheers, Al