Absolutely love the SID chip. The clever way of imitating chord-based triads by just rapid arpeggiating on a single channel was super cool to me as kid.
The SID chip is an analog semi-modular synth with digital control. The arpeggios unfortunately seem to be so heavily leaned on that it pretty much defines the chiptune sound, and those arpeggios could be played on lots of other systems, but the SID, when you dig into the beat frequencies and filters is a rich sonic world like no other.
