I have used Family Tree Maker to sync. to an Ancestry family tree but this has tended to be one-way, i.e. make changes in FTM and upload to Ancestry. I have also played with Legacy family tree which is quite a good software package. This has the ability to link to a (free) familysearch account: a facility which has not been used so far.
It's probably worth mentioning that the main database is The Master Genealogist which doesn't have the ability to synchronise with web-based family tree software. This is still a lovely bit of software if not looking too modern these days.
In a mood of experimentation I recently tried a couple of different approaches to see what I was missing.
1. Use the Ancestry hints and bring data into the Ancestry family tree, then sync. with FTM for a local copy, and
2. Using Legacy family tree and their ability to log-in to Familysearch and compare or find information on an individual.
In both cases the ability to inspect records about a person and bring that information into your family tree with a few mouse clicks is compelling.
In practice though I found it very easy to import poor information (e.g a woman's surname by marriage and not by birth) - perhaps this is simply a poor methodology on my part and looking at some training videos would help.
Conversely it was seen that in sharing data with Familysearch it could be easy to upload poor information to them which might then be passed onto others.
I have seen some Ancestry trees with completely wrong county names for some places, so maybe this is how it happened. The ability to import the source information is nice though, even if it is in Ancestry or Familysearch standard format.
To me the best feature is to be given information that I may not have noticed before.
I once read a comment from someone suggesting the best way of entering people into a family tree is to do it slowly individual by individual and get to know them as you add the data. I still think this is the best approach.
