Is your MD a UW model?

I have both the AK and AR. AR is good for simple bass synth sounds.

If you want pads, melodies, strings, brass, etc. Get an A4 or AK. Using just one track on the A4/AK you can write something that can make you bounce, plus the percussive sounds on it can cover 70-80% of the sounds I use on the AR. I started on the AR first because i wanted an Sp-404 on steroids wih analog drum synthesis and it covers that.