The main advantage over a portable is the speed of doing the job, you have instant heat and a constant supply of water (400ltrs).
I did a hotel on Friday which i had done in the spring of last year with the portable. Then it took two of us 5 hours of hard work to get it all done, had to hump the machine up two flights of stairs and refill/empty regularly.
On friday we did exactly the same job in less than half the time, ran 150ft hose from the van and I could have probably done it by myself in not much more time, as it was I did very little other than help with the hoses and prespray and the other lad did most of the work.
I also find that the vacuum even at 150ft is far superior to the excel which had 2 x 3 phase super vacs, so the carpets are noticably drier.
I can't compare it to your machine or any other TM, but at £5995 it is probably the best investment I have made for a good while and I'm more than happy with it and can now fit in a lot more work in a day.
Disadvantages are:
at this time of the year you have hoses outside lying on wet ground getting dirty
The 2" vac hoses are heavy, bulky and awkward to wind up/unwind
the van is a lot heavier with the machine (178kg) and 400kg of water.
you have to pay for your fuel to run the machine
there is little excuse to stop and have a cup of coffee and a chat, I find that now it's a case of, in, prespray, set up, do the job, tidy up, gone.