My friend bought his SD from this same guy at Malaysia's auction site, lelong for only RM90 (approximately USD27) including shipping. The delivery is very fast, he got his watch the following day after payment. The seller also communicates well on his email too.
But honestly, what you pay is what you get,.... when I compared with my noobmariner, the quality of noobmariner is much better, particularly on the bracelet parts - end links and diver's extension portions. As for the engine, I presume they're the same 21j Asian movement.
Nonetheless, for the amount paid, I'd say it's well worth spent. I understand from my friend that his SD is running abt +20 sec/day and has gone thru swimming, mountain climbing, and is still functioning well. Where else you can get one fairly decent SD with that price.