ive still got my old one, its a zt100 with the 20 hp command. fantastic for residentials half acre or less. i have both a 42" collection deck and a 48" side discharge deck for it. when this machine is in collection mode its a bit off balance, more so as it fills. doesnt hold a hill as well as id like but will do the job.
still cuts great and vacs as well as the walkers ive used in the past. cut not as good as the walker but close with fresh blades. with the side discharge deck on and the hopper off the back its a different machine. handles much better. invaluable for spring and fall cleanups. it definitely has its place.
fairly certain all the variations of this machine, no matter what name was on it or color it was, were made by the textron company out of wisconsin. its built like a tank. transmission isnt as powerful as the walkers. but again, its a tradeoff as this one is much easier and cheaper to service.
its not a fast machine but its versatile, affordable second hand, and i find it easy to work on. parts have been no problem. just freshened her up this fall with new seat and tires. still cleaned up nearly like it was when i got it.
some old pics: