I tried PCGen to build. A bard that used some stuff not from core. Took ages to work out how to get it to load up the additional options fully (and even then crashed and refused to load several times). One of the archetypes wasn’t working properly (removed light armour proficiency when it shouldn’t have and didn’t did longbow prof).
Would of been good if there was an option to add things in as house ruled stuff (such as forcing longbow proficiency, or adding in stuff that hasn’t been added yet like traits etc).
HeroLab I hated the buy everything route so have never tried it.
If you find things you don't think are implemented correctly file a bug report at jira.pcgen.org