Reply to Controllers' question and CDJ's

Hi guys,

I know this question has been asked many times in many different community s and I can assure you I read most of them.
But my question is a bit different: I have been djing for a while in a numark mixtrack pro and now I would like to upgrade my gear.
My ultimate goal would be to dj in CDJ's since they are sort of club standard.
I am torn between these controllers:
Kontrol S4
Pioneer DDJ-T1
Denon MC-6000
Xone:4D

The Kontrol S4 attracts me because it is really successful and many people recommend it.
The DDJ-T1 is also a choice because its layout is very similar to CDJ's + mixer.
MC-6000 and Xone:4D seem great because they can be used as a standalone mixer in case I decide to buy a pair of CDJ's afterwards and then they could be used a mixer.

Another option however more expensive would be to buy a pair of CDJ-350's + DJM 350.

Thank you very much!