hello...i've got jx-305 and i´m making dance and trance with it and it's extremely good for my purposes...quasimidi raven has better soundquality,more multimbrality,better effects and filters...sirius is quite same as jx305...the vocoder in sirius is very nice and you can make those kraftwerk-kind of robot voices and other really cool and impressive sounds...i think they all are good for dancemusic and it doesn't really matter which one you buy beacause you can make good dancemusic with all of them...