ive read that open back diff helps lateral stability such as it kinda helps prevent your truck from fishtailing because only 1 tire is spinnin out while the other is static. when one wheel spins out, it directs the power to the wheel of least resistance. the result is the traction-less wheels spins freely while the opposite wheel on the better traction surface provides little to no power. but since you are only runnin with 1 tire, it doesnt help with snow much at all depending on the situation.
i myself have lsd in my truck and it automatically kicks in when the spinning tire (or however you wanna call it) starts to spin, providing torque into the other tire with traction thus allowing it to grip better and hopefully find traction to the spinning tire again. the only bad thing about this is, if both tires are spinning then you have 0 control of the back end of your truck which could cause it to whip out (especially through snow)
so i mean if i were you i would go with lsd. if your truck has any traction problems with that, then you know it woulda been a lot worse with open diff. and if all hell breaks loose just kick it into 4wd lol hope this kinda helps