Well you also have to think about software.
If you want to stay with VDJ then the Beatmix is pretty decent and well designed, works well out of the box and can be enhanced with some nice mappings from the VDJ site (Pro version is needed for this though and Pro version is not included!).
If you plan on going the Serato route then the DDJ-SB looks very promising, I had no hands on time with it yet, but if it is as solid and thought out as the DDJ-SR then it will be a winner. However also plan for the 129 bucks upgrade fee to the full Serato DJ version! So the combo is also not cheap.
If you count in the upgrade costs to either VDJ pro or Serato DJ you would be in a price region beyond your budget and could prolly look into controllers already bundled with the software (for example the Reloop Terminal Mix 2 + Serato DJ bundle).