Shaun,
I saw the Airflex Turbo at Carpex and thought it looked pretty good. All the guys ive spoken to that have one have said that due to the large rear wheels its fairly easy to get up steps / stairs. If you decided to go for the Airflex Turbo 600psi it would be a good investment. If you were on a job using your truckmount and ran out of fuel or broke down you could simply plug the Airflex in with it in the van, put the hose from the tank into your TM fresh water tank and start cleaning knowing that you will be able to do a fine job. If you choose a porty with 2 vacs then you will really notice the difference at the wand. Im not saying the Airflex Turbo will have the vac power of your TM but it will have very good vac power.
Richie.