The differences are, alignment between the glass and bezel, the largest date. Loses extendable link. Three generations, the first 116660 smells of vintage.
There are still many Dblue 116660 in new condition,year 2017/2018 17/18k and I think also negotiable. 116660 black 2017/2018 in new condition are no longer available. reference 126660 with updated caliber there is many pieces available. This year the new 136660 was launched, updated in very small de
In my collection I have the old reference 116660 black dial, much rarer, and less inflated than blue d. The blue D was really liked by the resellers, who unfortunately cannot sell as they would like. If you do a search, you will see how many, too many d blue new old stock available.