The main difference from my perspective is that you have a hard drive so you're not going to go nuts running out of record time and spending $50 a week with those silly ZIP discs which the 840 uses.The 880 has 8 discrete tracks the 840 ties 4 together as stereo pairs I believe.THe 880 has 2 Digital ins and outs,the 840 has only digital out.More FX on the 880.Possibility of burning your own CD's with either Roland's overpriced unit or a computer based unit (840 would need optional SCSI interface to do that).Only the 880 allows for noncompressed recording.You may not care about this for demos,but you can hear the diff when you start bouncing data compressed tracks around. If you go for the 880 (which is what I recommend),get the 880EX,it has more FX and more inputs and better (although not by much) converters than the older models.Low price:$900-975,high:$1050-1100.Cheers
