For me I felt the SD4000 actually seemed to wear abit "smaller" than the Subc, most likely it is because of the Subc's rectangular case shape. The dial of the SD4000 is nice, but not as MATTE as it seems, tho not shiny. It does wear a touch "higher" than the older Seadweller but on the wrist is much better balanced than the 16600.
One thing that bothers me is the bracelet attachment to the lugs. It is not flush....apart from that I think its a spectacular price but I would not buy at retail, which I believe is £6900?