Reply to Used DJM-800 or New DJM-900 NXS ?

Long story short our DJM-800 went out and I gotta get a replacement.

I found another used 800 on craigslist for 800 bucks, and found the new 900 for 1600 bucks online.

I know the 900 has the quantization on effects, and is traktor certified, but is that really worth an extra 800 bucks in your opinion?

Our current setup is a pair of CDJ-900's, the mixer, and the S4 when we feel like using it. It's about 50 / 50 on the laptop with Traktor... sometimes we use it, sometimes we just rock the CDJ's.

Opinions are much welcomed! Is it worth an extra 800 bucks for the DJM-900?