I like GenJ because there is nothing you can't do with it, as long as you're willing to dig through the (admittedly complex) UI options. Very powerful, flexible and adheres strictly to the GEDCOM standard so compatibility is excellent. I have trusted this program with my family's history for more than 5 years. The only downside is the lack of a polished, user-friendly UI. I also disagree with those that claim this program is unable to track unions other than traditional marriage (such as civil unions and same-sex marriages). I've never had an issue with these subjects.
GenealogyJ is a totally free program, but has extremely limited use. It does not allow flexible relationships in families, is poorly designed, and awkward. It does make a lots of graphs and even a complete website, but not very impressive ones. I rate it only 4 out of 10 stars … but I give it 2 of those stars just because it is free complete genealogy program.
There are no 2 star reviews.