I great article on different types of differentials can be found at
www.4crawler.com/4x4/truetrac.shtml.
I am currently running a Winters Quickchange with a TrueTrac in it which is similar to the Torsen, and may or may not be stronger than the Torson.
Although I have spun it once with the TT, it has saved me at least a dozen times when crossed up in low gear (I know, I know, Ease into it Bob).
The main problems for me are using too low of a first gear, a direct cable to the barrel valve/throttle blades (tunnel ram w/ Enderle hat ...need a bellcrank), a GOB of torque, and old age.
The first two will be remedied before I run it again, I am going to fix the third with Nitro (is there any other way?) and as for the forth issue, I am increasing my dosage of 5 hour Energy drink, doubling up on metamusil and tripling the Ciallis (Doctor recommended). Bob