hi ,
well from my own experience please check out any truckmount probably just like test driving a car , make sure you can actually try it out on some c/c as when I bought mine the bloke quickly showed me it spraying water but only for a minute , try it out for at least half an hour to make sure you get & keep hot water , pressure stays constant , engine runs sweet , vacuum stays constant , what I found when I quickly saw it working then tried it probably when got home that the machine needed a full service , descaling , thermostat replacing , heat transfer fixing , all water filters cleaning , new vacuum seal , totall loss of water after 5 minutes and the list went on to cost me a small fortune.
so all I can recommend is please see it actually carpet cleaning not in some-one's drive / yard as there are so many things that can be hidden and if you need any more advice please contact me as would not like to see any-one caught like I was
regards
nathan