2010: Wright ZK 61'' 31hp kawi, Wright Sentar 61''25hp Reviews
2 hours demo on both - not bad, controls not jerky, but would take time to get use to.
Deck floats with the engine and doesn't bang against frame on bumps. Allows to go over rough terrain more smoothly at higher speeds (plus operator platform suspension, + seat suspension(sentar,) + your legs acts like springs & shock absorbers. All makes possible go over uneven terrain smoother, faster, with no problem.
Sentar feels more convenient & comfortable, seems have more potential. Choosing sitting or standing position allows better than on zk (or any stand-on mower) weight distribution - i.e. to shift center of gravity from above rear wheels while standing (good going uphill or over the bumps, etc) to farther back while sitting (better traction on turns, going downhill or backing-up uphill).
Advantage of smaller weight and size (trilor space) over ztr riders. Not significant on 61'' sentar and zk. It was only a bit lighter and shorter than regular 60'' ztr.
Luck of speed feels on both: sentar and zk.