I know I have posted a question about this before but now its really evident that I need to find a way to figure this out without missing something.  In my last post I was talking about with the help of Geni.com I was able to break the 1,000 names barrier.  And its possible to go back and forth real quick when relatives add one to two new names, or make minor changes to add to my main gedcom that I use with Family Tree Builder. 

But what happens when more relatives start getting involved with Geni, and (hoping here) alot of data changes, or gets added.  What is the best approach to making sure that both GEDCOMS are the same.  I already know that they GEDCOM on Geni is missing a few names, but I can't remember which ones, and I could possible have missed ones on FTB.

Is there a "good" program that will compare/verify two GEDCOM's and report the differances?  As a next step will it compare, and then merge (maybe not auto-merge) but give you the option on per change basis?  I am kind of new to this, I dont know if they current Family Tree Maker, Family Tree Builder, ect have this option as of right now. 

I know that I can download the GEDCOM from Geni. And this is the one that I would compare with FTB.  Any idea's or suggestions?