I owned a z355, was generally good, but mine was a 2001 model, it had a few deck and vibration issues, toro fixed these on later models.
I heard they don't make these any more.....they are very solid, and the low profile is excellent, go places where a midmount ZTR couldn't, but buying one could be meaning you are buying problems.
I would personally buy something in production, warrantee....
maybe the new exmark navigator if you need to bag clippings...