IMAP has three great advantages, from the user’s perspective.
We can summarize them by saying that IMAP is to POP what a file server is to a local disk.

Firstly, all messages and folders are stored on the server.
When files and directories are on the file server they look the same, no matter which PC you use to access them. They look the same ... because they are the same.
Same thing for messages and folders!
In other words, the neat folders structure you create in your email client (e.g. Customers\JohnDoeInc\in, Customers\JohnDoeInc\out and so on) is on the disk of the mail server, therefore you will always find it there, no matter which machine you access email from.
You have a PC home to do some after-hours work? You will see exactly what you see on your office PC; if you send a message, you will find it in the Sent Messages folder: no more BCCing yourself on messages sent from home, to keep track of them in the office.
Same thing with your mobile device: you access email with your PDA or your cell phone organizing messages in the same folders you will find in the office.

Second great advantage is that you can share folders and messages with other users, without copying nor replicating data.
You simply decide to share a folder, specifying which users can access and set their permissions. For instance user A will have full control of messages stored in the folder while users B and C will only be able to read them.
Once again the analogy with the file server is evident: you can share files and directories granting to other users the permissions you deem appropriate.

Moreover, servers are more likely to be backed up than clients. And the centralized restore is way faster and more efficient.
This applies to mail server as well as to file servers.
Even though we recommend that you archive all your correspondence in a dedicated application (such as Archive Server for MDaemon), it is necessary that your working environment is regularly saved to guarantee a fast restore in case of system failure and e minimum downtime.

A minor thing (not that minor, sometimes): using IMAP your email client can retrieve message basic information such as sender, subject and time of reception without downloading the whole message including all attachments! No more email clients stuck downloading messages with huge attachments that you don’t even need immediately. This issue is particularly sensitive over slow connections, such as the mobile ones.

To make it short, IMAP is a fantastic way to work with email and is eventually picking up.
With the growing diffusion of DSL lines and the increasing need of mobile connectivity more and more companies are migrating to this great protocol.

Achab Pop To Imap Migrator will greatly help you to carry with you your existing correspondence stored in POP clients during the conversion to IMAP.
It will make you save a lot of time: try it and get it now!