Dan, check out these links....
http://www.pmwf.com/Watches/GrandSeikoTable.htm
http://www.pmwf.com/Watches/Grand%20Seiko/23Movement9S55JohnDavis.htm
An inside look at the Seiko Morioka Watch Studio...
http://www.morioka-seiko.co.jp/Eng/atelier.html
The 9S55 movement used in this watch is regulated to six positions and temperature. I believe the accuracy to be well within +5/-3 secs per day but I could be wrong. The movement is hand assembled at Seiko Instruments Morioka watch studio.
Here is a sample of the factory accuracy report enclosed with the watch as part of its document set:
23RatingCertificateScan.jpg
In comparison to a Seiko SARB, I think this Grand Seiko is a bit smaller but not by much. It is a work of art :-*
The SARB range borrows quite a bit of styling cues from these Grand Seikos. It is a timeless and classic watch.
If your end goal is to keep 2-3 nice watches in your case, I can see this Grand Seiko fitting that role quite nicely.