I have my family trees on Ancestry and MyHeritage. I also have DNA results on FTDNA and 23 andme but I do not use their family trees.
Geni belngs to MyHeritage (or the other way round), and both sites use each others' data. I agree the data on Geni is unreliable as there is no checking of data. Geni has given the wrong birth dates for some first cousins of mine (someone must have mistranscribed the data), and this wrong data was being copied into others' family trees.
There also seem to be people putting others' family trees into Geni who are not related (and where we have not given permission for them to do so), and they make mistakes as well. I pointed out a mistake to one such contributor (unrelated to me) who was putting some details of my wider family tree from JRI Poland -going back in time- into Geni, but they did nothing to correct it. Their interpretation was different from mine, but I had family information she did not to support my view.
I think this is a major failing of Geni.
Jill Whitehead, Surrey, UK