I had bought the Porter Cable 4" Whisper Series about a year ago. I previously used a 3x21" Sears. Did the job, but this PC is in a whole different category. Some of the more important features: Positive tracking-when you set the belt adjusting knob, the belt stays adjusted. Some belt sanders creep on you, and require frequent resetting. Annoying to say the least. Also the belt change feature is nice. A simple lever you pull out, then push back in. Quiet-you do not have to wear ear protection to use this. Hearing protection is always a good idea though. It is heavy, but to me this is an advantage. You don't have to push down on the unit, in order to get the job done. To those who mention that you have to keep an eye on the machine, because it can take away too much material too fast, that is because they are using a coarser grit than is required for the task. Finer grades give you more flexibility, and removal is more gradual and even. A belt sander is not designed to replace a finish sander.