If you intend to make a lot of fonts or large fonts, then go for the Professional Edition. It has a lot of features that automate the otherwise rather repetive task of Font Creation, such as glyph transformations, merging of contours, autokerning, etc. See my review page and the Comparison Chart
Version 5.5 will soon be upgraded to version 5.6, which has signficant improvements for both Home and Professional Users. The upgrade is free, whichever version you decide on. See the Announcements Thread You can, of course, pay for the upgrade from the Home to the Professional edition if your interest in Font Creating takes off. There is a lot more to it than meets the eye.