I am totally happy as it is right now with Denon DJ …
Where I have the best of both worlds 
I have a Numarks Mixstream Pro & Mixstream Pro ‘Go’ model at hand. Both running on Engine DJ OS.
When I play long sets I bring over the PC for convenience reasons using MIXXX as DJ software.
It supports also multiple external libraries from other DJ software brands …
When I play smaller sets I don’t attach the PC and can use MIXXX to export the tracks to USB. So Engine DJ OS can access them offline. Or even online if you export to Dropbox for example
It has never been better 