We've used them at the store for about 8 years. We still have 2 that we've used the whole time. You don't have to push down as hard, so if you're cutting all day long, it's easier on your shoulder. The grippers come loose sometimes, but we just clean them with water and a paper towel and they stick again just fine.
They are in the way for smaller accurate cutting, but for cutting yardage, it's great.