I use the 2000, so thats all i can provide.

Beat fx are on par as the 900 in terms of "what kind" of beat fx are available for both mixers. However, the 2000 beats the 900 by a long shot in this side due to its 3 EQ fx knobs to control which frequency you want to effect while using the fx.

Thats alot more control than what the 900 can provide. Some may say its not needed, but I feel every bit of control is giving the DJ a extra more organic touch to their mix.

The intant fx, vary in differences as the filter knobs of each channel are from 0-100, instead of -100 - 0 - +100.  This measn the 2000 knobs are litereally on and off knbos instead of 900 where you can have 2 sides of filters to control. Both are good, I enjoy my 0-100 knobss.

Theres also the LED screen, now i rarely use it, but I have seen people use the frequency mix with success (my self included) but its kind ofhard to incorporate when you have so much other controls you can mess with on the 2000.  Obviously the 900 has the spiral and gate fx for instant. 

For me the problem with 900 is i can swich my beat fx quickly, and more pricesly, meaning i cant just switch from trans all the way to echo due to the fact they arent next to each other.  With a EFX-1000 style of lay out on the 2000, the access of your fx are quite simply a button away. Beat timing as well is a button away, the 900 has the XY pad, so the execution of style of mixing, and mixer-work is differnet.

The work flow is similer up until the way you use the mixers fx in my opinion. 

summarize:

2000= more control of the fx ; parameter knob for instant fx, and EQs for beat fx.

900= more instant fx, and quicker execution of fx ; no need to fiddle with EQ's or paramets and straight up action mixing

Thats my take on it, but again, i dont use the 900 so my opinion may not be the same as other people on the forums. but DJM-2000 all the way for me

@Transporter > SpeakerHandz did a great job analyzing the mixers in my opinion!

I would just like to add about the built in sound cards and recording.

The DJM-2000 has a built in sound card standard at 8-channel output no input at 16 bits. This sound card can also be switched to record directly via USB cable as a 6-channel output 2-channel input at 16 bits. Lastly it can be assigned as a 6-channel output no input at 24 bits. This allows you to record 2 inputs maximum at 16 bits. You can use free third party software such as Audacity.

The DJM-900 also has a built in sound card but offers 8-channel outputs and 8-channel inputs all at 24 bits. This allows you to record up to 8 inputs maximum all at 24 bits. This is means it is higher quality as well as more channels that the DJM-2000. The DJM-900 is also Traktor certified and allows you to use the built in sound card to control your timecode in Traktor 2 software. This means no more carrying your external sound card and extra cables to gigs just so you can use Traktor. The DJM-900 replaces the sound card all in one and works even better in my opinion.

Just something to consider in my opinion, but overall it depends on your DJ style, how you use your mixer, and what type of features you would prefer to have and use most often.

If you're able to, check out your local Pioneer DJ dealer and play around with the DJM-2000 and DJM-900, you will probably get a good feel of which one is right for you. :)

Best of luck deciding! 

It's a tough choice.  Most points have already been covered in the replies.  I had a DJM-800 and upgraded to the DJM-2000.  I've had a chance to use a DJM-900nexus and my final feeling was that I was happy I had the 2000.  Price is very similar and both mixers have unique features that make each one desirable.

Focusing on your FX requirement though, think about what you prefer the most.

The 900 offers very quick and "instant" effects, some of which are new and unique.  When I tried it, my thoughts were, "Yeah that's really cool, but now I've turned the FX on and off a few times, now what?".  The 2000 offers much more control and creative potential thanks to the beat effect EQ knobs and its EFX style configuration - don't forget it has had Quantize and a really cool new reverb added via firmware updates, and a sampler which everyone seems to forget about.  I find myself coming back to it again and again, experimenting with what you can do with it.

Both FX are not quantized when you use Serato or 3rd party program (like me)

I finally choose DJM 900 because its more looks like DJM 800 and it's better for a dance music dj.

The 2000 would be cool for house \ techno \ dubstep dj, but i'm just working at weddings.

Definatly regardless of which mixer, Any-one of those mixers are great choices for any DJ of any style. Glad you have made your mind up. It's hard to see other mixers in comparison when compared by "user-friendly-ness", "user-friendly-functions" and "user-friendly- lay out"

I've tried some vestax mixers and allen and heath, I just enjoy the pioneer look, feel, and design. But congrats on the mixer

The 900 is a fantastic mixer but i'm so glad i went for the 2000. I couldn't go back to a rotary knobs for effects, fair enough it has the X-Pad but the beat buttons on the 200o are more precise 

Yes...but the Crush Effect on the Djm 900 is better i usw now the Djm 2000 and i think the Crush effect is realy bad for an Flagship Mixer from Pioneer ;(
But i hope they can fix this ita an Pioneer Product and the effects can be the same ;)
Thank you and greets From Austria

I think the crush is just fine. 

Again two different kind of mixers

900-  crush is set at a particular parameter already. Similer to the HPF being set to a particular parameter already. Which in turn means your cursher, and hpf will always sound the same every time you use it.

2000- Crush fx alogn with parameter will play to how well you know the parameter - filter knobb relation. My experience on the 2000 tells me that how i alow the parameter to play into the fx usage can allow me to use the crush or any other color fx in more parts of my mix, while not making it sound over used.

But thats my opinion. I only know the 2000. my opinion does not in anyway down play the djm 900.

What i said above is true for each mixers instant fx. I used crusher and hpf as examples, but it explains for each mixers capabilites in their own respect