Randall Newton has a positive review of McDwiff on the TeamDWF site:
McDwiff uses API calls to Autodesk Freewheel to render design data. You get the smooth user interface of a Macintosh application with Autodesk technology for processing DWF files. So you know the rendering of the design data is accurate. The quote at the end of the TeamDWF article sums it up: "McDwiff is great to use, fast, easy, simple – and it works. Thumbs up."
Check it out. Also see http://www.macdwf.com/.