Well i thought of the SD but it is a lot bulkier and now I have the sub it is a nice size, no problem getting a cuff over it and no-one noticing your watch, my Fortis and TAG are much bigger and the sub is a nice change. Also i didn't want the cyclops.
No my understanding is that M serial 14060 sub is COSC but the others are not, however it is the same movement as in COSC watches from Rolex just not COSC, makes the face neater.