I used the "big brother" 2455. 4 years, except for the brushes, nothing has changed. I work as an electrician and do not worry about the load on perf. Bought this thing. The result hasn't changed. Everything is fire. Almost a year and dozens of flats made and thousands of holes. Live perf. For those whining about weak drilling with a crown. Have you heard of diamonds? 3min 42sec. This is the time of 68 socket boxes in reinforced concrete. Don't skimp on the tooling. The perf itself is gorgeous