Welcome to the SCWF. There is a lot of WISdom contained in the brains of our members!
I own a 36000 bph Lord Marvel. It keeps great time but is not the best Seiko ever made. Its purpose was to prove the 10 ticks per second on a mass produced scale. Watching the second hand move like fluid is mesmerizing. The build quality of the case and dial and fit and finish are on a par with the King Seikos and Grand Seikos of their time, in my humble opinion.
The Vintage Grand Seikos keep far better time, at least when new. The King Seikos are right there except not quite all the way for time keeping and have a separate look.
Any vintage watch, without exception, is only as good as its internal condition. One slightly bent or worn pivot, spring, parts location/wobble/alignment can render them far from original specs. The point of a vintage GS is not super-great timekeeping, it is the feel, look and aura of a vintage peice, and yes it can be serviced as good as new too.
Modern mechanical Grand Seikos are far far better than the vintage GS's in every way, consistent with advances in parts manufacturing.
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