Roland • D-20
The D-20 makes a great budget or alternative D-50. It's more closely related to the D-10 and D-110 synthesizers but adds an 8-voice sequencer with a rhythm track. The D-20 is a digital synth that employs linear arithmetic synthesis (LAS). It's a confusing synthesis / editing method composed of tones, partials and timbres. Basically it all boils down to tricky programming which, if you know what your doing, can have interesting and unique results. Reverb effects and internal / external memory storage are also available on the D-20. Definitely worth a listen.
http://www.soundonsound.com/sos/ jan05/articles/roland.htm
"The same synthesis architecture lay at the heart of the D10 and D20 synths, and their rackmount equivalent, the D110. Again, these employed the limited LA synthesis pioneered by the MT32 so, in comparison to the D50, they sounded uniformly uninspiring."
Lets make it clear here to all those idiot EBAY sellers who HAVE to mention the D-50 in their 'other D series' adverts to boost their resell prices. None of the synths other than th D-50 contained the 'FULL LA' Engine, none sound like the D-50. The D-70 included.