I struggled at first with my small TM, having used top portables for 23 years with excellent results. The reason was I couldnt get the solution metering right. I raise this point because, the results I used to attain with a portable (100 psi, twin 3 stage vacs) were no worse than I now attain with my TM. The solution leaving the wand jets now is much more diluted due to the extra pressure and hence the more water used. Of course the argument is that the extra pressure heat, etc. compensates for the lesser solution strengh. Obviously this doesnt come into it, if microsplitting.
The thing is, on results alone, i.e. cleaning appearance, I cant say they have improved for me, since changing to TM from portable, other parts of the job have (speed, faster drying etc) but not the clean appearance.
Though having less power, I think the portable job can be made to be first class, through harder work, technique and a more potent cleaning solution.
Everything together, of course, taking into account the quality of clean, speed of drying, speed of job etc. the TM wins everytime.
Lee is correct though, in that the goal posts are moving all the time. At the moment an absolute minimum I think is the 100 psi with twin 3 stage vacs, however with more and more TMs coming into service, I can see in the not too distant future (only a few years 3 or 4) that the TM will become the only acceptable norm for professional HWE cleaning. This is already so, with most present day TM owners.
Dave.