Should I get the S2 or S4?

[PVSH]

Hey Guys,
i want to buy a new DJ Controller. I have the Reloop Beatmix with a LPD8, which I use with Traktor. And I decided to upgrade to a S2 or S4. But I dont know which one. The S4 costs 200€ more than the S2 and i never used more than 2 Decks.

I know that there are some Functions that only the S4 haves, but I never used them, so I cant tell if I will ever use them.

So what do you guys think, what should I buy. If I buy the S2, i could also buy some AIAIAI TMA-1 Headphones.

[SlvrDragon50]

S4.

Filter knobs are worth it.