Great to hear you're happy, and since Midi Mapping only recently came out I think you can expect to see it evolve with future updates!
So far so good but can be much better
I own a Pioneer DDJ SX2 and I used it 2 years with Serato, since 3 months I tested Rekordbox and I am much more satisfied with this SW than Serato, the results was that I bought a licence of Rekordbox and I moved all of my Music Library to it, Rekordbox in my opinion has a much more simple and nice user interface, is more intuitive, offers more functionalities and is much more stable than Serato. Besides that you can also use only one SW for Controllers and CDJ for instance.
My only complaint at this moment is regarding the MIDI mapping functionality that is really very limited and the only reason I see is because Pioneer do not want to open all functionalities of the SW to a MIDI controller
Despite this I am happy with Rekordbox (current version 4.2.1 in a Windows 10 Sony core i7 laptop).