I have used the Mytee HP60 Spyder for 9 years and it has been a great unit for my Shop...
Yes, it does cost more than the Mytee Lite, but I wanted 3 motors, heated water, big tanks, and huge water lift all out of 1 cord..
Very easy to maintain - I run some Distilled White Vinegar through the system at least once a year, and never had an issue with anything..
What I read a lot of people doing is putting too much water down, and then not taking the extra time needed to extract it all up, or not having a machine with enough water lift to get most moisture up and out..
I tried out ProChem products at the beginning but quickly found that something like Meguiars APC+ is really good, foams very little, doesnt need a lot of water to work, and leaves a nice scent..
Finally, I found my way to using my VX5000 Steamer with the triangular brush with a white towel on it, to apply steam into carpets through the towel to the carpet that had been sprayed with APC+ and brushed, then use the Extractor only to remove even less moisture and I have really hit a sweet spot with this part of the Detail..
I have only had to use Mytee in Costa Mesa, CA I believe once to order some velcro hose connectors I believe, and they were pretty good at that task..
Know nothing of issues, chronic or not with the smaller version, but I can see how modular this machine is, and all the parts are easily accessible and replaceable, without even having to go to Mytee for anything.... Its just motors, pump, heating element, 3 switches, under there..
Have been on a few carpet cleaner forums in the past, and that world is full of people that are just as opinionated as some of our best here...

What they are doing and what we are doing on little carpet footprints (compared to theirs), is way different in that they are using huge power, pressure, brushes, etc., heat, and lift..
I have seen people use those little machines out there and while they may work for some things, I dont believe they will ever have enough power to really lift the moisture out of the carpets unless you want to spend extra hours holding that machine on each square inch of the wet carpet..
My carpets always come out dry and soft and standing up.. Those that are not rinsed and extracted very well come out hard and stiff and get dirty again very quickly..
I think that the carpet cleaner industry or whoever made the Water Lift test, should perhaps someday change that test to the Wet Sand Lift Test, and see how that works out..
Good luck with your research !
Dan F