Here are a few links for a review on the SP-808. Keep in mind that some of these are from 1998 and some stuff has changed like OS and PC/MAC editor the EX version which uses 250MB media instead of 100MB media.
http://www.soundonsound.com/sos/aug9...landsp808.html
http://www.sonicstate.com/synth_revi...id=670&print=1
http://www.harmony-central.com/Synth...ampler-01.html
Scroll down to Roland on the left side then to SP-808
http://www.vintagesynth.com/index2.html