It really depends on the vehicule. Is it a car? Don't bother!
Is it a minivan, or SUV? It may be worth it. Weight is a big factor and many vans and trucks just don't have enough "heavy" in their duty, especially minivans. Even the "Japanese" vans have transmission problems because the transmission are just not tough enough for the weight they carry, especially when you decide to go get a load of bricks or something like that.
In such a case, it is worth it for $150.00 installed.
Cheers