Better off getting the Traktor S2 or S4?

I’m looking to get the S2 just to get things rolling, pretty new to the whole DJ’ing thing so this will be my first bit of hardware. S2 is the more obvious choice because it’s £200 or so cheaper than the S4. But, I don’t wanna spend all this money on the S2 and then suddenly feel quite handicapped at only having 2 decks. Up to now I’ve never really tried more than 2 but i can see how it might be useful. So do you think it’d be better to go for the S4 so’s to be better safe than sorry?

Thanks, any help is appreciated!