I've got one of the earlier models about 8 years ago before the prices came down and it's still working as it origionally did! The StatPower ProWatt 150 to be exact.
There are two things that you need to know about these gadgets. First, they don't put out a normal sine wave so if you plug an alarm clock into one of these things it will run at about triple speed so that doesn't work. My father tells me one of his electric razors didn't work with my brothers newer model so he got another razor and it did work (he has a RoadTrek van he uses for camping) Second, if you try to use a soldering iron with one you'll find that the tip of the iron is grounded to the frame. This means you can't solder to live wires unless you pull the fuse for the circuit. One handy tip is to get rid of the cigarette lighter connector and use a sturdier connector with an on/off switch and replace the fuse with a breaker. The lighter connector will make the power flicker whenever you hit a bump.
There are booster boxes now available with inverters but they don't seem to be as good. I bought a MotoMaster one in May and after 6 months of being in my transport it was dead. The dust or possibly the vibration made the inverter part fail although the rest of the box worked. Even so, it is worth the money to have one since you can use it to power stuff in the bush without a noisey genset.
Steve