The most heavily debated beta topics was the magnifying glass. The thread on this particular feature generated well over 100 responses, and in the end the original look of the feature was changed based on feedback received in that discussion.
In 2009 pressing the "G" key will bring up the magnifying tool:
By zooming in with your mouse wheel, you will zoom only the area of the model contained in the magnifying glass area. Zoom out, and you will zoom back out. To move the glass, you move your mouse to the edge of the glass and drag it around.
Another feature while you are in the magnifying glass tool is to section the model:
By holding down the alt key while zooming in, you will create a section of that portion of the model. The section will appear parallel to the screen.
In beta this tool was especially handy in large assemblies where you want to avoid rotating the entire model to see an area to convert an entity, or to select something to add a mate.
As mentioned earlier, this tool was widely debated. In fact the original tool as shown in the original whats new book looked like this:
This is proof that participation in the beta program yields changes to the software. Some recognition should go out to Matt Lombard who was a vocal voice in getting this changed, and also to Jim Wilkenson from Solidworks who was a good sport about the whole thing even in the face of a sometimes heated discussion. Ultimately these two guys set in motion changes to what can be a very useful tool.