Although it is best if you have a listen for yourself, i can only give you my own opinion on the sound of both units as i do own both.
The 2500 sound is a stadard digital clean sound, no such magic color. I can say that the sound is also a little scooped out in the midrange compared to my XL and 4k. Lacks full on detail - just resample and you will see.
The 2000 XL has a different sound to the 1000, 2500 and 4000. Its not as warm as a 3000 (although i do feel that the 3k sounds dull in comparison to the new mpcs), but it has a presence in the upper mids that make drums poke out in a mix. Also the XL has a nice punch to it imo.