Pros/Cons of wireless LAN

My office is in charge of setting up a LAN in a 3 story Court House that is 100yrs old. The floors are about 12″ thick concrete, and the wall jacks have to be run in a surface channel.
We were told by one company that wireless would be theway to go. I have not had any of experience with wireless networking and would like to have more info than this company’s advise.
Any experiences or site links would be great.
Thanks,
JRWild