When choosing a porty there are quite a few qualities we should be considering just as Shaun has pointed out.
Power is not the be all and end all, build quality, quality of service and value for money are all relevant.
Most of the top line portables on the market will allow the operator to use extended hose lengths of 150'+, this is useful if the machine is to stay on the van, a bit like a TM.
Just as important is for the machine to be easily removed from the van and taken closer to the area which is to be cleaned.
Most of us can only comment on service when something goes wrong... that's when you find out if the supplier is good or bad.