Wellington have the best tail IMO.
And in perspective the Knights have some of the worst top 7s today: Wilson, Parlane, Devcich, Marshall, McGlashan, Yovich
CD: Pinga, How, Worker, Sinclair, Taylor, Patton, Griggs
Well: Bell, Brodie, NParlane, Merchant, Boam, Woodcock, Nevin
Auck: Guptill, Jones, Bopara, Styris, Kitchen, Boorder, Raval
Cant: Nicol, Papps, Fulton, Stewart, Astle, Anderson, van Wyk
Otago: Haig, Morgan, Todd, McCullum, Broom, Boorder, Wells
CD, Wellington, Auckland and Canterbury are comfortably ahead overall I'd say. Otago seems a bit weak, but with Cumming in the team they have one of the best opening combos around, ND have pretty rubbish openers compared to everyone else.
One of the better attacks though, Scott and TBoult are two pretty big guys domestically.