Briefly compare packet-switched networks to circuit-switched networks

What will be an ideal response?

Packet-switched network: Typically always available but shared among users; traffic is routed on a per-message basis, admitting traffic onto the medium as it is generated based on priority.
Circuit-switched network: Media is used on demand; this occupies the entire media bandwidth for a connection (like phone calls) ;these circuit connections can often be virtual now, so it reserves some amount of available bandwidth for the connection instead of using all of it.