Quality-wise the Denon is built like a tank. It packs a lot of features in a 19″ form factor. The drawback to that is that some people feel it’s a bit cramped. I personally never had the problem with the mk1 and the current mk2 has been restyled to feel better ergonomically.
If you are a mobile DJ and intend to take your controller on the road too, I’d say in it’s price range it will be hard to beat the Denon.
I know that with the mk1 Denon actually supplied a license of VDJ (in the US, Europe was Traktor), so I am gonna guess the mk2 will work with VDJ without any problems.