As a student living with little money, upgrading and expanding my DJ setup is difficult. You will find that any equipment worth your while will be worth the usually large price tag and as such, the value will tend to exceed a bank balance such as my own many, many times.
So I will first of all explain what I set out looking for so that I can determine whether these two bits of kit truly are worth their hype.
I have a standard controllerist's setup: my controller (Mixtrack Pro 2) and my laptop. I bring these to gigs and set up with the Mixtrack's outputs feeding into a spare channel on the house mixer. The issue with this is in some clubs, there is very little room in the booth. Picture a CDJ-2000 Nexus setup with a pioneer mixer in the middle, filling up a booth, and then me turning up with my wide(ish) Mixtrack Pro 2. This poses an inconvenience since for my controller to fit, I'd have to remove some gear already on the table or, rest it on the platters of one of the CDJs.
So this is where DVS comes in handy, I may as well use the control surfaces (CDJs) already available and slot a small mixer/serato interface in the middle to control with my laptop. For extra effects, another slim unit could fit in and still be narrower than the Mixtrack Pro 2.
These two units also exceed the above parameters for performing by removing altogether the need for CDJs/Turntables if necessary and working as a modular setup.
Akai AMX (left) acts as the mixer and interface while the Akai AFX (right)
is a powerful effects controller with deep Flip integration.
For typical setup configurations: