The Gripper is a Weisman-type LSD, which we used in our 300-bhp rally car (see my avatar). These LSD types handle transitions much more progressively than the Quaife Torsen-type when you set the preload low (we typically set a breakaway torque of about 60-ft-lbs.) so the handling on twisty/snowy roads is much better in my experience. The black magic bits are in the clutches/friction material, oil and the ramp design for the pinion gear shaft to ride up on (which is what presses the clutches together). And yes, I can attest to the marketing claims that you can drive the car out of a stage when you break an axle...
As you point out, these units are not maintenance-free like a Quaife. The clutches will wear and toss some friction material into the gearbox. If I were doing one for a street car, I'd go with the Quaife. But if I were doing serious track days frequently, I'd go with the Torsen unit for better handling -- and best to add an oil pump and filter for the gearbox fluid to get more mileage out of the gearbox and your ring and pinion gears.
Hope that helps,
Mark