Its a pity some of the guys with a lot of TM experiance can no longer post on here.
However some are still about and will help you.
What do you run now?
Alltec is missing from your list - make good machines.
What has been said consistently in the past is
yes look at the machine and its spec, very important obviously
but you buy the machine once, you then operate it for many years
so after sales service is probably top of the list
couple with that but less important is the nearness of any support when things go wrong.
I have a TM and find benefits over the portable I still have.
Like you the bucket work with a porty is a pain, but obviously you still have to handle the hoses and more often then not MORE hoses because you may not be quiet as near with the TM van.
Its great not having to empty the dirty water into a bucket then down someones loo,
but you still have to dispose of it, I get home, have to raise a sewer drain on my drive, get a hose out to empty the dirty water tank, and because there is not much fall between the drain on the dirty water tank and the driveway I have to empty the hose as well.
On a TM you have a n engine, a large pump, a blower, a heatexchanger, fresh water pump, more electrics like starter motor, battery. All of these need more maintenance then a portable.
Lots of pluses and lots on minuses.
Benefit I find though is on the job - the efficiency.
If I was buying new I would have to weigh up carefully what market I was targetting to detrmine what size of machine iI needed to do my market.
Right now, if I was to be buying new, I would look at a low end Hydramaster (318 or 321), or the Prowler. Prowler has the price advantage and will do all domestic jobs and more then adequate for lot of commercial. Hydramaster always gets good comments for after sales service.
Just take your time in choosing.