For what it's worth, Thomas, here is my experience. I should say, to begin, that my purpose in joining both WT and FS was to share my research with all my relatives and others who might be interested but do not want to pay for Ancestry.
I have a fairly large tree on Ancestry (10,000+ profiles) that I consider well-sourced. When I joined WikiTree two and a half years ago, I added my ancestors profiles one at a time until I linked into the main tree on (nearly) all my branches. For the most part, things went well but I ran into a couple of major conflicts with existing PMs. I have not added all my Ancestry sources to WT, but I have begun listing my Ancestry tree in the See also sections.
About six months ago, I decided to also try and add my ancestors to FamilySearch. I'm sorry to say that I found things there rather more screwed up. I don't really blame FS, because it is so much larger, and older, but I will say you might find more cleanup needed, and probably experience more people editing your ancestor profiles, often with wrong information.
I do know people who love FS, and if I spent more time there (it is one more thing to get used to) I could probably get things cleaned up better. You do not have to add your sources all at once. FS, like Ancestry, may give you hints which will make the process easier.
On FS, you have the option of clicking on the "Following" star on any profile, which will give you a way of monitoring what happens to the profiles you care about.
On WT, you should check your watchlist daily, and a new option is that on any profile, you can click the Changes tab, then choose to review changes to all ancestors, descendants, or connections.