Hi there
Advantages of Cache Mode:
Cache mode is basically used for keeping copies of your emails on your local pc. So when your outlook is offline (is not connected to your exchange server either due to network issues or because you have a laptop and you are not in the office or not connected to the network), you can still see your emails upto the last time you were connected to the server. When in offline state (the state that Outlook is in is displayed at the bottom right of the outlook window) you can still read,reply and create new emails. New and replied to emails are queued up till the next time you are connected to the server and then they are passed onto the server for delivery and new emails are downloaded.
One of the bad things about cache mode, like offline folders (cache mode is sorta like offline folders for outlook) is that if there are errors which are not noticed, you wont really know about them. I had a client who lost about 1Gb of emails due to cache mode. what had happened is that he moved pcs and i recreated his outlook profile with cache mode on because he has a laptop now. during the initial sync there was a network failure and because his mailbox was like more than 2Gb half of it disappeared. Luckily he noticed it and informed me and after searching for it everywhere i finally found it in sync issues\server failures.
My advice: If using a desktop, stick to non cache mode unless you have intermittent network outages or are connected to the server over a slow link like vpn or wan link
laptop users are more suited to cache mode. this is an excellant technology but as with everything, there are prices to pay. make sure your users are aware of the sync issues folder and do check it at times to ensure that nothing is caught there or there are no issues listed there.
A small article from MS can be found at
http://office.microsoft.com/en-us/outlook/HP010000671033.aspxTry googling on cache mode. I normally stick to real life reviews from users than MS for stuff.
Hope that helps
Cheers