Before you begin with FamilySearch.org please first understand that it is a COLLABORATIVE website. Aside from living relatives, EVERYTHING else is shared and subject to communal editing. When I read through the critical or negative reviews I came to the conclusion that they were written by people who do not really get what a collaborative website looks like. There is no "your" tree! There's only one single, communal tree. It is very similar to WikiTree and in many respects both websites have a similar mandate and a similar philosophy.
Now, for a review of the site itself.
The interface is simple yet remarkably powerful. It has a wealth of well-chosen data sources--in some cases missing from the commercial paywall sites. And, the search algorithms, once you figure them out, are also extraordinarily powerful. Depending on the part of the world you're researching FamilySearch may be the perfect research choice--for Dutch genealogy, for example, I can't see a better website.
I've been using it for four months now and I have not found any software or any website that is anywhere near as powerful as FamilySearch when it comes to building a family tree. If FamilySearch.org were to be spun off as a privately controlled family tree website it would bankrupt MyHeritage and maybe Ancestry--the interface is second to none and it's trivially easy to document your work. But, a lot of people don't like its collaborative nature.
Much of my work happens in the Netherlands and the coverage of records is stunning.
In the right parts of the Netherlands and with a bit of luck, it's possible to use FamilySearch.org to create a properly sourced, RELIABLE tree for an individual dating back five to six generations with only a few hours of work. YES, six generations in a few hours of work! Because I'm working on DNA matches with Dutch relatives I've now created full ancestral trees to prove a connection--and more than a few times I've managed to replicate an entire tree in an hour that almost always matches the family tree that the match had for their ancestors (sometimes mine are more complete, thanks to the search algorithms for FamilySearch.org).
As for conflicts with others--I've only run into two individuals who have conflicting views to mine. In one case it related to a differential interpretation of the facts, and I think our amicable solution (to document the different and equally valid interpretations of the documentary record) was satisfactory. In another it was someone who took "ownership" over an ancestral branch that lacked documentation. Since it was an undocumented branch I left their fantasy alone--genealogy without documentation is fantasy and should be ignored unless it interferes with the proper functioning of a site.
That said, in a few cases I've had auDNA hints that suggest that some ancient connections (early 1700's or even late 1600's) may indeed be correct. I'm not prepared to accept those connections as valid without a lot more research but it's indeed quite interesting.
The one thing I've always wondered about is the affiliation with a church. So far I've not seen indications that's a problem. What I'd be more worried about is that it's a website hosted in the US and the US has extraordinarily weak privacy laws.
PS It's too funny. This is only "second" review at this website. It seems that I reviewed FamilySearch in December as well. I can't see what I said the first time around but this one is now informed by many more months of experience.