Reply to Set-up advice?

Hi, Newbie to the site here....
Ive been looking for the andwers to my Q's for a while but cant find anything so apologies if its a duplicate question...


I currently use Traktor and Virtual DJ (depending on venue), a NI Audio2 soundcard, and a Pioneer DJM800. I dont use a controller but instead use hotkeys on the keyboard.

The venues I play at range from having no gear to CDJs and Mixers, etc.

I'm looking to upgrade my system but undecided as to what to go for.

Either go for Traktor Scratch A6 or A10 - and use CDJs where available, or hotkeys, using my existing DJM800

Or go for a Kontrol S2 or S4 (S4 can be used with VDJ), which presumably I wouldnt need a mixer - just plug straight into the venue's mixing desk like I do with my mixer?

If I go for a S2 or S4, are they as good and easy to use as a DJM800, and is the sound quality reasonable?
Can the S2 or S4 be used with Serato if I went down that route?


Thanks in advance!

Matt