Ok, someone has to say it, so it might as well be me.

Why not go the whole hog and invest in a Truck Mount?
Here's why. (Hang on......................................................ok, flak jacket and bullet proof vest on now!
A Truck Mount is far more powerful than any portable.
A Truck Mount looks far more professional than a portable.
A Truck Mount is far faster than a portable and so can earn you more money per day / week/ year.
A Truck Mount you can do almost any kind of job, domestic, small commercial, large commercial and therefore you will have far more of the market to aim at, instead of the very limited market a portable will give you. This is a point lots of newbies miss when starting out and end up restricting themselves to the domestic market which in these recessionary times is not a good idea. ( I know portables can do commercial jobs but often the time taken to complete the work is unacceptable to the customer and the performance of the machine severely limits the speed with which you can do big jobs)
A Truck produces a far better result and leaves the carpet a lot drier, even on the dirtiest of jobs.
A Truck Mount in the right hands can practically print money.
Right, I'm off to hide in a corner somewhere.... bye!
