The main question you should focus on is whether or not you want to work with a laptop. The DDJ-SX is a great tool, but needs a laptop for it's software whereas the Aero works stand-alone. I have the 'old' T1, but I don't mind taking a laptop with me everywhere.
Other questions are, why would you want Serato? Do you know what it's capable of? If not, go and figure that out. It should make your choice a lot easier!