I bought a copy of the Imagaro Z on their special. I won't put the product down but it gets rarely used and has serious shortcomings.
To expand however, I should point out that I am evidently more concerned about accuracy and precision than any autotracing application alone can ever satisfy. I have at my disposal, Imagaro Z, Corel X3, Illustrator CS2, Gerber Omega 2.1, Adobe Streamline and FlexiSign Pro 7.6.2.
Out of all that I use Flexi 99% of the time but rarely stop at just a trace. In fact, more often than not, I find it faster to draw with the Bezier pen and use geometric shapes where appropriate along with Flexi's excellent weld and cutout tools. When I do trace, Flexi has a number of different tracing applications included which is helpful for different types and conditions of artwork. Once traced, I use the path cleanup tools in Flexi for graphic cleanup. I rarely will keep traced text which is where autotracing has always come up short. Instead I will identify the font(s) and typeset it over the image. When I can't then I pick something similar and node edit the text to match the image.
As far as identifying type, this has been discussed to death in other posts. The short answer for identifying type is to read about type and learn something about it. Only then will using Imagaro Z or FontExpert be of any real help in DIY identification. I use a font manager for visual comparison, FontExpert in tandem with Photoshop for automated ID's, and Imagaro Z when all else fails (which has yet to ID something in that situation).
There's nothing wrong with using What the Font? except that it is like giving a man a fish instead of teaching a man to fish. It solves your immediate problem but you don't come away any better at your craft.