The 1100 is comercial quality, versus the Linksys SOHO quality.
The 1100 will support multiple VLANs & SSIDs
The 1100 will integrate into a managed wireless system
The 1100 has the same CLI and GUI as the other Cisco Aironet products, in the event your organization's needs increase and you need to expand or upgrade.
I'm sure there ae a bunch more bullets, but they all pretty much relate to the 1100 being a product designed for a commercial environment and the Linksys being designed for a Home / SOHO environment.
I believe you'll find that the 1100 also works better at farther distances, and is more tolerant of inteference and environmental noise.
Good Luck
Scott