I have the CP4. Had to play left hand bass in church this last sunday. the CP4 was awesome ! You pick whatever performance setting you like. hit split, and it automatically adds a bass, which is easily changed to whatever (acoustic to finger bass, etc, by using the + or - buttons. you can turn the bass (split button on and off easily. So we would start the song with a light acoustic sound, and then I would add the bass as the song got stronger. It was really good.
the acoustic and EP sounds are awesome, and it has a really good selection of backing pads, which are the nuts and bolts of praise music.
Im working a jazz gig this weekend with it. Will let you know how that goes.