By the way, Hi James! I'm that American guy.
Actually, a portable and the right operator can outclean a truckmount run by a fool. The number one advantage to any system is the operator. With that spoken, yes, I believe truckmounts offer more soil removal. I don't know if I can mention the carpet and rug institute (the association of the dudes who make the carpet) but they have a rather remarkable ability to test soil removal ability using XFR technology developed by NASA. Those basic results are available to cleaners on the Carpet-rug.org website under SOA (Seal of approval).
By the way, cleaning is the routine removal of soil, 15 year old sofa's that have never been cleaned is called restoration.
No steaks for the price of a Hamburger.