Living individuals can be entered but are not viewable or accessable to others.
No nagging as the site is not feature limited. With the exception the images of some sources which are hosted on third party sites which require payment for access to the image or a visit to a Family History Center. No ads.
Printable fan charts, pedigree charts, family group sheets.
Ability to send messages to other users working on the same individuals.
Does not support same sex marriages or incestuous (parent-child) relationships.
Cannot directly upload or download a GEDCOM. You have to load the GEDCOM into one of the free programs that syncs with FamilySearch (Ancestral Quest, Legacy Family Tree and RootsMagic), then sync to upload. As you sync, you will be asked to resolve any duplicates. This may take a long time, but it prevents duplicates, and you may find some additional information about your ancestors.