I have WL 1600s and use with PW remote (Flex 5 / AC 9 /AC 3) on D800e (used to be D700). The difference b/w AB and WL are: (1) Built quality WL is sturdier and heavier (2) 2 mode setting in 1600 and 3200 WL full power and 1/8 power with 8 stops change v.s. 6 stops on AB.
Einstein and WL / AB 1600 are the similar output power and if I were to buy the unit now, I would get Einstein without any doubts but it was not available when I got my WL. I use this in a small studio / large studio / desktop (as replacement of speedlight) / location- I must say I use more than my SB900s in off camera manual setting .