Why would I want a Zone Director?

[bdillard]

I might want one but I can't seem to find out what it gives me over unleashed.    I have 8 offices throughout CA with about 4APs per office.    I have them set up unleashed currently.   When we set up a new location, we clone an unleashed AP and bring it to the new location.    We have about 200 approved MAC addresses.     We typically use R310 units.   Each office has a site to site VPN between them.   Any suggestion on why I would or wouldn't want one would be helpful.   All I can find is that they are for centrally managing APs.   Not much beyond that - e.g. do they give me a larger MAC access list, do they help with something that isn't available on unleashed versions?

Thanks

[bdillard]

Thanks Albert that is good to know.    So if Zone director is less than ideal does this UMM help me easily change the approved mac list and passwords in sync between locations?    Our employees move from office to office on a regular basis so it would be nice to have a single source of administration between locations without the drawbacks of latency if the VPN between sites is slow or unavailable. 

Are there any online videos or free training modules about it?   I watched 2 videos and all I found out is that it is linux based and you can buy a bunch of license skus.    I'd like to know how to install it and how it helps me centrally managed a bunch of APs at different locations (I'm not looking for a video that tells me it can do that but HOW it does that).