A week or two ago, Passwird asked about the Garden Claw.
I now own BOTH Garden Weasel's Garden Claw and the Garden Weasel.
The Weasel is the thing with all those silver "blades" that interlock. There are three of these spinning wheels and you can remove any of them to get various effects. It works ok and has a lifetime warranty. The problem is that they really aren't blades in that they aren't sharp. Therefore, it is good for turning fairly loose soil, but it can't chop things.
The claw is a set of angled tines that you push in and twist. It tears through almost anything but solid rock and also has a lifetime warranty. It is much better for spot work than the Weasel, but for aerating it will take forever.
Hope this helps