The SDGM series are lovely watches. I have both 001 and 003.
The price seems a touch high but there have been rumours of their obsolescence. I'd consider looking to buy new from the Japanese market. If you do find one it'll probably make slightly less of a dent in your pocket than the buy it now price of the one you've highlighted.
Build quality, for me, earns it the moniker of Baby Grand Seiko. Some will argue that the 6R15 movement is not that great but of the 40+ watches I own, at least 8 or so of them are 6R15 driven and their timekeeping and performance are beyond question.
I doubt you'd be disappointed with that model if you can secure one.