my locker experience is with suzuki, but i found the front locker invaluable.
i used autolockers front and rear.
a cvjoint broke first time out, but i think it was just a fluke, 'cause i didn't break anymore after that.
broke the axle in the carrier once also, but that was me- doing some rock hopping on the dusy-ershim. still had 3wd. still got home.
i learned how hard to hit it.
i know nothing of how welded gears would work, but either way it would put more stress on things.

autolockers(&welded, i'm sure) don't make good daily drivers, but i don't tow.
worth it off pavement, i think, and the mitsus i've run with use 'em.