Well, here is my concept of the rm1x, i just bought mine three months ago. before i go farther, i also own a mc-303, and after much research i decided to buy the RM1x,...and i guess i got so used to the mc-303, it was hard for me to change modes. However, the rm1x offers much much much option than the mc-505, i know that...i did alot of research on this subject. The only good thing about the mc-505 is the concept of the d-beam which i think is the dumbest thing ever made. the concept is neat, however....who cares....you want to make music, not show your friends that any retard can wave his hand over the beam and make noise. I am still trying to learn the rm1x, and trying to figure out other ways of emulating the arpegiator that the mc-303 has on the rm1x....peace