I would like to preface this review by saying that I have almost every wireless porter cable tool available. The only other tool that worries me a bit is the cutter wheel because of the power, but that's because it's battery powered. I have the wired version in case I need some heavy lifting. Now to my utter disappointment with this grinder. I work wood not only for myself, but also for customers. I needed a new random orbital sander to replace my old one and thought this might be a good option given the number of battery powered PC tools out there. It worked fine the first time I used it. I've used big batteries and run on one battery for a while. Power delivery was moderate, but when the battery hit 25% it was very noticeable. Then about 2 months out of the 4 months I had, I noticed the on-off switch started working. I would have to twist it several times for it to turn on. Then a few days ago he started falling face down while running. I thought it was the battery, but even fully charged and working batteries had no luck. And finally, last night trying to finish a large batch of orders for clients, I got so sick that I just gave up. I went to the store this morning and bought a new Dewalt grinder and it blows this one out of the water. Unfortunately, this computer did not suit me at all.