a lot of the choice is preference. torsen / quaiffe gear-types are much smoother in transitions of torque while clutch types have a more digital effect which annoys some drivers. a high torque biasing ratio helical can make a car handle strangely, oversteering when hevily crossed up - not great. clutches can be a little harder to live with in very tight slow corners. some real positives for quaifes.

clutch types work when a wheel leaves the track, gear types go full open in that case. clutch types tend to be substatialy lighter too. prices on old school style clutched diffs are much lower, and guys like Steve Eckerich can often turn your factory diff into a clutch LSD, so you don't need someone to "make" a specific diff for your car. win win win clutch.

there are newer hybrid style out there, such as the OSGiken or Wavetrac that use a geared system to distribute torque smothly but also press clutches so the diff truely locks up. these are likely to be the best once better developed if they aren't already. they suffer from weight but deliver the best of both worlds. the inertia of a diff is actually pretty low given their high mass as they are relatively small, so the weight is more of a located mass than a driveline loss issue.

for the money - I haven't seen anythign as good as a Steve E. conversion. you can spend a lot more for a lot less.