Hello,
I had the same thing. It is what you want do you want 4 decks or just 2. And there is a Traktor 2 demo what you can try sadly there isn't a Serato Itch. Most of the functions of S1 you can find also in T1 only the SLIP function you don't have on the T1. And If you upgrade to Traktor pro 2 then you have much possibilities. I for one have chosen for the T1.