Typeset makes finding fonts easier for both professionals and normal users. The program's GUI lets you quickly preview all different fonts to select the one you like to use. You can drag and drop fonts straight to your Finder. Typeset can let you organize all your different font collections, which you'll find in a list on the left side of the interface. Clicking on a particular font will summon the side bar, which shows specific properties like style or unique name. You can also set favorite fonts and edit them in detail, by changing things like color or size.
Generally Typeset is much faster than Mac's Font Book but we've found the application to crash if you try to load too many fonts at the same time. However, on the whole, thanks to a clear interface and a good selection of tools, Typest makes for an easy way to find and test out new fonts.
Typeset is a good choice if you need to preview all sorts of fonts quickly.