This means you will have to drive around AGAIN, and you still won't get everything. It will be faster and more cost effecient (sneaks vs tires, bearing, hyd. motors etc etc etc) to buy a string trimmer.
I think it has its place, like if you have alot of fences to trim under or if you mow cemetaries. here is a website of another comapny who makes something similiar. I saw these at the GIE looks to be a well built unit. Plus they have 3 models, 2 electric and one hydraulic.
I would like to here from someone who has tried some of these trimmers or has seen them in action. If they worked they would save a great deal of time and work. If you could run it as you were cutting there would be many areas that it could be used for. If I had to make 2 trips around a lawn with it, it would be a waste of time but if it worked while I was mowing I think it could save alot of time in many lawns. Maybe cut half of the time off trimming or even more. That could make you much more productive and take the place of an employ for trimming. (If it works?)