Model 4212 arrived today and took about 45 minutes to install. It's very easy if you've ever set up a drill press or just worked with one. My mileage is very reasonable (contrary to some other reviews) and it works great. Its best feature is variable speed. Now I'll actually set the right speed for different jobs instead of leaving it at medium speed for each job because I'm too lazy to mess around with belts. Speaking of my shortcomings, I wrote and submitted a review this morning. , which states that lasers do not work. Not true! Thinking about it, I remembered that the tool comes with 2 AA batteries, which were never mentioned in the instructions. So I figured out where to put them (under the black plastic plate next to the laser switch) and installed them. (The protruding plastic box has a small plastic tab that you press to open the panel.) Very simple. This solved the mystery of the non-functioning lasers. It would be nice if Wen mentioned installing a battery in the manual for nerds like me, but overall it's a great little tool for something that sells in the $200 range.