Like Ancestry, My heritage, and all the other such like sites, it depends and what sources are cited. Some are totally useless, some are excellent, For my own family history except for Geni and Wikitree here, nearly every other sites have stuffed up some of my family history, non existence wives, children etc, writing to all the managers laying out your case with sources cited etc, it makes no difference to them. They just cling to the idea that they are descended from some one famous, regardless of the facts. So treat all the information that is not sourced with some scepticism, try to find other sources.