I think he has the most powerful jab in the business p4p, but its not the best.. the list goes something like this
Wlad
Wright
Kessler
R. Marquez
ODLH(look at his fight against Mayorga)
Taylor(great jab)
Cotto
Mayweather(isn't as effective as it used to be, but its still very strong and fast and accurate)

The funny thing is both Wright and Kessler's jabs were pretty much nullified by Calzaghe and HOpkins compared how they normally work, but Kessler's really set up his right hand against Calzaghe, and Wright still controlled the distance at some points against Hopkins.

That being said I can't believe nobody has talked about Wright except Amat. I mean since 2005 he has dominated Trinidad with it, and he badly outjabbed both Taylor and Quartey in their encounters.