Both are quality units. At the time when I got my Quaife, the prices were about the same, but Quaife had the advertised warranty, while Torsen's is implied. Both are equally strong units, with the Torsen having a slight higer biasing ratio.
But with the Quaife prices on the rise, the Torsen looks to be the better deal.
2003 Ford Focus ZX3 2.3l N/A = 221 HP, 162 ft-lbs, firstname.lastname@example.orgMPH - SOLD
2006 Ford Fusion 2.3l Turbo = 244HP, 247ft-lbs
2014 Ford Fiesta 1.0; Turbo