Being multi-modal ie. having individual access to each parameter on each voice via dedicated knobs & switches makes this synth a boon for hands-on synthesists. It's brute force approach to polyphony - having four individual Synthesiser Expander Modules (SEMs) each acting under the control of a master programming module - eventually became the standard via separate voice cards within analog polyphonic synths.
Though the oscillators are fairly stable, it is a bit much to ask to keep all 8 in tune over a long period of time without tweaking them. Not recommended for live applications. It's voicings polyphonically were good, but it's strength lies in its unison stack. One SEM can sound raw and biting, two begins to give a rounded woolly tone. All four pours forth a wall of bright, smooth power. A very rich and rewarding sound, more full than any other lead I've mustered on dozens of other synths.
It is quite weighty, around 60 pounds and the keyboard hasn't a facility for multiple triggering but a nice final output module allowing a different volume and pan for each voice is a nice touch. The Four Voice also comes ready to link up to a separate bank of four additional SEMs to form an 8-voice.