Gloria,
You are talking to someone that owns three Arbortech tools. I have the mini grinder, the power chisel and the big grinder. I have nothing bad to say about any of the tools. The mini grinder was the first one I purchased it sure removes a lot of wood in a hurry and I have never had it bind or catch it is super safe. What I would advise though is that you get the carbide blade for it if you are carving anything big or hard. I find that the harder the wood the better the minigrinder works. The large grinder is very powerful and can remove a lot of wood fast, it comes with the carbide tip.
The Arbortech Chisel is a work horse and really is great for large carvings and that is mostly what I do I am a tree sculptor. I would caution you if you purchase the chisel that you are careful not to pry with it, it will snap the chisel. Arbortech are very good and will replace any chisel broken but it can take some time.
Hope that I have been of some help to you if there are any other questions you need answered please dont hesitate to contact me
Colin
http://geocities.com/partridge_ch