Easy to configure
Easy to use
Easy to set-up
Can be maintained by one person
Cheap to run
Can be expensive to set-up
Attractive targets for hackers
Allows networking over large distances
The bigger the WAN the more fault tolerant it becomes
Very expensive to set-up and maintain
Will need a full time team of network engineers or people with equivilent knowledge
Usually always a node down somewhere that has to be fixed
It's convienent
It's not secure as wired
Its not as reliable as wired
Its not as far reaching as wired
It's not as fast as wired
It's more expensive than wired
Its not as easy to set-up as wired