It was intended primarily for live performance of pre-programmed patterns consisting of up to 16 tracks of MIDI data.

Roland's literature states that the MC-909 has "new-generation XV synthesis", the synth in the MC-909 is a very similar sound engine to that of the XV-5050 64-Voice Synthesizer Module.

The number of PCM waveforms is 693, ranging from vintage synths to strings, drums, guitars and pianos.

Straight playing via an external keyboard is however possible directly from the sequencer mode by simply selecting one of the 16 tracks (parts) where a patch (voice, sound) is stored.

There are tricks from user forum sites that have found ways to go beyond this limitation using xD-Picture Cards as other means for storage.

The "pattern" in the groovebox concept as developed by Roland (and thence adopted by other manufacturers) is intended to be a 4-to-16 bars-long small musical phrase made up of 8 to 16 tracks.

In fact, there is no recording or sequencing capability in Song mode besides pattern chaining and some playback settings.

The Roland MC-909 was used by the hip hop producer RZA while working on the movies Blade: Trinity and Kill Bill.

In fact, even when the machine was released in 2002, it took Roland Corporation 5 years until some of the more complex bugs (like the inability to store RPS patterns) were fixed in the operating system upgrade v1.23 in early 2007.

Another common complaint refers to the unit's size, which makes it less portable than a laptop with a midi controller.

The unit has been designed with only a 2-prong power inlet, without a ground lift; hence, there have been complaints of light electrical discharges from its metallic body when handled with less-than-dry hands.

Roland might refer to the end users' requests for effects that sustain past the point when the pattern switches as they "developing a future new product".