Works well, reverse is a good feature, it's very noisy and the collet comes off pretty quickly. My snap on and cleco grinders are much better. It's on par with my master grinder, except the master doesn't loosen.
I've been using it at least a few days a week for the past few months and it's still amazing! It is important that the tool performs well at low speeds! I often cut large bolts and fairly thick steel. I also use a lot of 1 inch brushes with scalloped ends and they do this tricky job very well!
So far my favorite straight grinder. The inverted version on it is great. I would just like to find a 90Β° die grinder with the same option. The only part that's a bit annoying is that the head falls off from time to time and it feels like your airflow has dropped. It's okay, tighten it back up and she'll purr again. I'll probably be ordering another one soon and hope Air Cat makes a 90Β° version of this in the near future.