In original STP we had 4 port-states.They are
Rapid spanning tree and Original STP are compatible.In original STP Root bridge only send BPDU to other non-root switches and they receive it on their root ports.But in RSTP all switches generate BPDUs every two seconds (hello time). This is the default hello time but you can change it.
The original STP uses the max age timer (15 seconds) so MAC addresses could be removed faster from the mac address table. In RSTP, BPDUs uses as a keep-alive mechanism similar to what routing protocols like OSPF or EIGRP use. If a switch misses three BPDUs from a neighbor switch it will assume connectivity to this switch has been lost and it will remove all MAC addresses immediately.
Original STP used to reject inferior BPDU. BUT RSTP accepts inferior BPDU(as the backbone fast feature is enabled)
Rapid spanning doesn't use timers to decide whether an interface can move to the forwarding state or not. It will use a negotiation mechanism for this
Rapid spanning tree can only put interfaces in the forwarding state really fast on edge ports (port-fast in original STP) or point-to-point interfaces. RSTP uses "Sync" mechanism instead of the “timer-based” mechanism that the Original STP (listening -> learning -> forwarding)