It benefits from having an external controller to get under the hood of the exterior to program your patches. You can get an original Roland PG-300 external controller to program custom patches, but, Roland no longer manufactures these.
Thankfully there is a modern-day equivalent in the form of the Kiwi Technics PE (Patch Editor) which can be purchased new here on their website if you are finding it hard to find a used PG-300.
It has 1 DCO per voice, pitch bend, LFO, Sub, pulse, sawtooth, noise plus a sub-oscillator to form your patches. Pulse width, portamento the classic chord memory for old-school rave and techno sounding riffs, and a chorus effect has been thrown in for good measure.
This model has a successor in the form of the Roland Alpha Juno 2, the newer model added MIDI and keyboard improvements over the Juno 1.
It has been used in the past by acts such as The Prodigy, Massive Attack, Vince Clarke, Human Resource (the dominator/hoover sound early rave music)!! And many more.