Right out of the box, the 2000 sounded fuller and richer than the 3000. The 3000 is flat as a pancake until it is tuned. Once tuned, there is a dramatic difference. After tunting, when I played them side by side, using the same or similar onboard styles, there was no comparison--the 3000 sounded better. And, when I tested this, I did it with the onboard speakers turned off and ran both through a small mixer and to an external sound system.
After my evaluation, there is another test that the keyboard must pass as well. I do the same test with my wife and daughter doing the evaluation, but not letting them see which keyboard I'm playing. When you've been married to the same woman for more than 4 decades and you have a daughter that is equally as critical as your wife, you're gonna' get an unbiased opinion--whether you want it or not. Both said the 3000 sounded better to them, even when using identical onboard styles.
I'm a sincere believer that every keyboard can sound good to excellent in the hands of an accomplished musician/entertainer. However, that keyboard, regardless of make or model, will sound a lot better when tweaked and tuned both for the venue and the individual sound system it's being used with. For that reason I have two user EQ settings on my 3000--one of which is tuned for the Z-5500 system and the other for the Barbetta Sona 32-C system. I cannot emphasize this aspect of arranger keyboards enough.
PSR-S950, TC Helicon Harmony-M, Digitech VR, Samson Q7, Sennheiser E855, Custom Console, and lots of other silly stuff!