Hello all
I've been using those kdbs for more than a year, and I got some conclusions about them.
I'll start by saying my opinion about the pros and cons of each kdb.

3000:

Pros:
Good voices with emphasis on pianos, eletric pianos, strings, flutes and wood winds, sax and some accordions. I dont like the sinth & fx voices. The most part of the voices are well equalized, with proper level of volume.
Another good point are the styles. Well constructed and suitable to my repertoire.
Menu: pretty easy navegation!
Style control: well placed buttons and easy to opperate.
Memory control: perfect.
Multi pad: very usefull for who knows how to create according their necessities.
Microfone input.
Style Creator: very easy to use
Fade in, out button.

cons:

Lack of a second input for mic.
Vocal harmony: not suitable for profi use.
Lack of harmonizer and sustain buttons.
Difficult visualization of the screen in very ligthed places.
Smart media slot: unnecessary
Lack of bass inversion button


ROLAND E50

Pros:

Some excellent voices with emphasis on organs, accordions, vocals (scat voices are awesome!), sax and sinth voices.
Styles: few innovations. It makes me feel like playing my old G800. Otherwise something is usefull: Live band, Jazz and Latin banks.
Usefull bass inversion button.
Very interesting cover and Style Makeup Tools( To modificate styles and arrangements).
Usefull Easy Setting Buttons.
Screen: visible in any place, with any luminosity.
Lighted buttons, easy to opperate.
Very usefull balance knob (acc x kbd).

Cons:

Kbd touch: Although roland's fame, the kbd is hard to use with some voices as sax for example. For the first time, I had difficulties playing a Roland.
Menu: a bit confused and user program as well.
Intelligence Melody (harmonizer): not suitable to second (layer) voice.
Lack of fading in out button.
Lack of dedicated buttons for intros, fills and endings.
Transpose button: hard to use
Octave change via menu.
Storage system: slow and confusing

Finally I'll say that I like both of them, but if I had to choose one, I would prefer the 3000.

cheers
Chico