Hi Wally
I have a friend who worked at Woodcraft for a few years. When I was looking for a power carver, he told me that the Proxxon and the Merlin both were returned on a regular basis by most people who bought them. Some, because they quit working, some because they just didn't hold up very well.
I bought the Arbortech, (the whole thing, not just the extended arm that you can attach to an angle grinder) and have been very happy with it. I use it primarily for roughing out work. It is very aggressive; I clean up cuts, when necessary with either hand-held carving tools, or a reciprocating carver. I also have a Weecher, which is both a rotary and reciprocating carver. For an inexpensive carving tool, it's not bad, and the Weecher is fine until I can afford the Foredom.