i agree, your mileage may vary.
this AT545 has 310,000 miles on the clock, slips, overheats, makes noises you never want to hear, has the fragrance of burnt oil, but has kept on going.
after all the inputs..... i dont think i'd have a problem with a rebuilt 545. i think thats smart money.
however, fixing it doesnt address any of the shortcomings of the setup.
if money were no object, i'd go for the mt643, plus a new ring gear in the differential.