I've heard good things about the Auburns, but have no personal experience. By the time you pay for the setup and the posi, $50 is pretty small. Get what you decide you want.
After having owned a truetrac and several different clutch type posi setups, I much prefer the Truetrac. Better in the snow and ice steering wise. Just as good traction as the clutches when new, better as you start putting miles on. Less mechanical stress because the two wheels are never "locked". No additives to worry about. No clutches to wear out. If you keep the rig long enough the Truetrac will be cheaper as you won't be replacing clutches. The only con I can think of is that if you have one wheel in the air, you have to use the brakes a little bit to get the truetrac to deliver torque to the good wheel. It needs some very small traction to get the torque to split. Not really a big deal. Just give it a little brake. Not required in any other condition I've encountered.
Anyways, that's just my opinion. Others may have a different opinion.
After having owned a truetrac and several different clutch type posi setups, I much prefer the Truetrac. Better in the snow and ice steering wise. Just as good traction as the clutches when new, better as you start putting miles on. Less mechanical stress because the two wheels are never "locked". No additives to worry about. No clutches to wear out. If you keep the rig long enough the Truetrac will be cheaper as you won't be replacing clutches. The only con I can think of is that if you have one wheel in the air, you have to use the brakes a little bit to get the truetrac to deliver torque to the good wheel. It needs some very small traction to get the torque to split. Not really a big deal. Just give it a little brake. Not required in any other condition I've encountered.
Anyways, that's just my opinion. Others may have a different opinion.
