I have had the Roland JV-880 module for almost 8 years and traded it in for a JV 1080. I always liked it very much. Now you can get it for cheap on Ebay. I would recommend you the JV-1080. It has better and more filters than the 880. The 880 only has low-pass filters while the 1080 also has high-pass and band-pass filters. The 1080 also has a more analogue sounding resonance than the 880.
How come the makers don't make the essential information for the musician to understand & probably arrive at something else for owning this JV-880 thing? Probably they don't know how to translate in, well, English...with accuracy. (Ho-hum)
I personally think they make great instruments & sounds. I own Roland E-Drums & samplers. They still sound good after all these years. They sound better when interfaced with effects & other stuff.
Come now, guys, give us a break here. Please?