I'm looking at getting a sentar sport for my business. I do alot of hills that I mow with a dual hydro walk behind now. I wondering how the sentar sport is for very steep hills. Is the sentar and the stander the same chassis or are they built on different platforms. How are they for getting over curbs? Is it practical to walk behind the sentar, or is the seat in the way. I'm looking at a 2008 sentar sport demo with 50 hrs for $5800. Is that a fair price.