Here's what they say:
ROLA-8000 is an accurate simulation of the Roland CompuRhythm CR-8000 drum machine from the early 1980s. It features 325 samples including multi-dynamic and round-robin variations of the original sounds.
All the rhythms and intro/fill-ins have been re-created as well as the other functionality of the original such as programmability.
Enhancements to the original include a full mixer, "free fills" that play randomised fill-ins based on snippets of existing fill-ins, and a MIDI file recorder.