I personally like the clean look and feel of Traktor. However, I don’t know much about Serato and I’m sure the DDJ SX2 will get you very far. Another thing you could do, which is what I did, is get Native Instrument’s Kontrol X1 (about $200) and pair it with a mixer, like the z1 (also $200) and you can expand from there. This works great for those of us who are, unfortunately on a budget, but ultimately the choice is yours.