my point about horsepower is that it is really easy to add a spare machine to a courier cluster. If my boss said heres an old pentium, can you throw it into the cyrus server pool it would not really help. Wheras throwing an old server into a courier pool is very easy and the extra horsepower gained is helpful.
If I only had one machine I would use cyrus. It is more efficient, but if I ever had the option of recycling secretaries computers for mail servers I would use courier.
ok...so...cyrus don't have a bunch of authdaemons, a tcp server that accepts connections and then forks a handler?
it is less resource intensive perhaps due to less IMAP features?