For how long have you been using it?
Nearly 2 years

Did you try many other models before getting this one?
I have already mixed the dns 1200

What thing do you like most/least about it?
+ for:
- They are very beautiful
- Solid and responsive (except USB mode c is a little slower but nothing serious)
- Accuracy of the plates (bpm, jog and pitch) is excellent!
- Self loop is very handy

For:
- No hot cue (at this price that is bad)
- The price ... I've had them at 550 euros each which is very correct but given the increase (almost 700 euro) I find it a bit too expensive.
Ultimately the cdj 400 are very good turntables robust, responsive and accurate! They are however still relatively simple and quite expensive.

I advice to any dj who plan to chain a lot of small to see larger parties!
that is reliable, thanks to the USB you can have all its securities does matter where