Over the years, Deere has put a lot of effort into making sure their equipment was incompatible with anyone else's. 

I like having couplers that are compatible with everything else....I just wish they worked as well as the old ones (or 50 series) do.  I wish our 'brand x' stuff worked as well, also.   The MT635 is pretty good, but everything else we have had over the years has been a pain in the butt...including the 7700 Deere.