I am purchasing a new trimmer soon. It will be the handlebar style with a harness. I have a very long ditch and a pond embankment to do. I was looking at the Stihl FS130 and FS250. Does anybody have experience with either of these? Are there other models I should consider? I have also noticed they offer several styles of harness'. I almost forgot, this is not turf type grass but more tall weeds. Although the ditch is too rocky to use a blade.