Do you mean the Propane ones? (used to be marketed by "Propex" I think). If so, there have been a number of posts over the last few months. Try doing a search.
I have a small 1.6kW one and have had it for 3 years with no problems.
I know of one that was very reliable for a number of years until the motor got filled with seawater. They are a good deal cheaper than some of the opposition but I believe that their spares are far less widely available. If your range is limited to Western Europe and USA they must be very good value.