It is possible to access most, but not all, features when using WebDAV to access MS Exchange. All features, on the other hand, is available when using Brutus or MAPI.

Well.. to be honest, only the client relevant features of MAPI has been implemented in Brutus, but those missing (which are mainly for service providers) can be implemented easily, should a requirement surface.

Hard documentation from Microsoft is impossible, or at least very hard, to find. I have asked around and tried to dig up as much information as possible. The following are features of MS Exchange that are impossible or extremely hard to implement using Exchange WebDAV, but possible or much easier with Brutus:

• No usable WebDAV for Exchange 5.5.
• No service provider stuff possible at all.
• Much better filtering in Brutus using restrictions.
• Awkward access to properties.
• Most PR_OBJECT properties can not be accessed.
• You can access the PR_ACL_TABLE and PR_RULES_TABLE properties as binary blobs, but you have to parse them yourself.
• The WebDAV based security descriptor in Exchange 2000 is reportedly buggy. The Exchange 2003 one might be better...
• Access to the PR_MESSAGE_ATTACHMENTS property is cumbersome for Exchange 2000.
• You can not access the PR_MESSAGE_RECIPIENTS property at all in Exchange 2000 WebDAV.
• Some store-level properties are inaccessible.
• Exchange WebDAV notification are not as usable as Brutus notifications. One example is that you are unable to figure out exactly which object was deleted when you get a delete notification.

There are probably more features that are difficult or impossible to access in Exchange WebDAV, but the above entries are at least some indication of the difference of Brutus versus Exchange WebDAV.