Fast waveform redraw like Denon Prime
Please look at below animated screen captures, as you can see waveforms in Rekordbox are laggy when you skip around or drag the waveform with the mouse. I don't have a Rekordbox controller to test with but I imagine this also happens when operating the software with a Rekordbox compatible controller:
Now let's look at Denon Engine. It's instant, no lag at all.
I realise Denon Engine is not full-blown DJ software (though it's only a matter of time before it is) like Rekordbox DJ, but it's worth noting that Denon Engine is able to display more bars horizontally than Rekordbox which is very useful for aligning tracks in advance. It also allows setting hotcues any length of time before the song start, good for cueing songs that have a bit of non-rhythmic audio (e.g. a scratch or speech) before the first down-beat, for example: