I notice a big difference between terramites, and I think these factors are often overlooked when judgement is passed on a terramite.
Skimpy T5cs- There is a rental shop who rents a T5c by me and theirs is a skimpy T5c. Not only the Add-ons- but the Digging Arm Thickness itself. Like their machine is a slimmed down skimpy one. I rented it, It's light and has a hard time on dense gravel ground, etc..
Beefy Ones- I own a 1996 Terramite with the 18 briggs engine. The engine died so I replaced it with a 25hp Kohler. Compared to the rental store, mine is BEEFY and BIG.. I have all the optional Add-ons like 31' Floatation Tires, Urethane Foam Filled tires for weight, Thumb, Loader Side Spikes, etc. And the Frame itself, along with the Digging Arms and all are much beefier and bigger than the rental shop one.
I have no idea how the new ones handle of today, I know they look different..
When you hear a review for a terramite, keep in mind that there are several different terramites of different proportions and abilities out there.