It has some impressive performance figures and they were honest enough to print the not so nice things in the Reviews
4x4 Aust Ron Moon "The problem with the Unichip is that it is hard wired into the wiring loom and takes a qualified technician all day to install and set up the system - which adds up to a considerable expense. It also limits who can install the system and where it's available. As well, once it's installed it's not an easy job to remove, making any fault-finding on the vehicle's fuel injection system more complicated."
Probably ok if your doing a lot of on road towing ect, I dont think the extra HP would of much benefit offroad