One of the best features is that it can do a fetch Medline (function F5) when connected to the internet. You just need to enter the PubMed ID and it automagically extracts and stores the data in the bibtex format. All you have to do then is to give it a key.
And best of all, it is free as in beer (i.e. zero cost) and free as in speech (i.e. open source).