How reliable is the information on Geni and Family Search.? Is one more reliable than the other?The quality of the data completely depends on the specific family/branch and the habits and abilities of the users who have worked in your part of the tree on that platform.
I find it vastly easier to attach sources on FS; I think Geni makes it well-nigh impossible to create citations. Judging by the dearth of sources I've seen on Geni, I'm not alone in this opinion.
Regardless of which communal tree or trees you use (there's also WikiTree, and I think WeRelate still exists?), it's part of the nature of the beast that you should keep an offline (or at least private online) backup of your family lines. Yes, it's extra work, although there's software that can help (that I keep meaning to explore).
For the private online option, both Ancestry and MyHeritage are plagued by the same perpetual paywall problem: unless you shell out large sums to them on a regular basis, you get black-and-blue from running into the dratted things. Unfortunately, the link between MH and Geni means that you get the worse-than-teasers All The Time on Geni, too. (And the "best" part on MH/Geni is that it will cheerfully try to get money from you for the _tree_ data from FS, as if it were equivalent to historical record data, and as if you weren't the person who put it on FS in the first place.)
It's "choose your poison", really. FS and Mormons, Geni and paywalls, WikiTree and not-quite-coding. But I do believe in the communal tree concept; it's a whole lot better than the re-re-copying of utter dreck that goes on (because it is actively encouraged) on Ancestry.
. /\ /\