I'm looking for a mobile device to use for work, and am thinking of an N9 because of how much I've liked past versions of Maemo...but I'm having trouble getting a sense of how robust the Exchange support is compared to other devices/OSes out there? I've searched and found a fair number of complaints, but I haven't been able to tell if those complaints are failures of the client, or if they are because the user has a unique setup that might not be fully supported.

So how good is Exchange support and the email client?

Are contacts fully synced and available locally, including all extra fields and description (most of my contacts will have things like assistant information, multiple phone numbers, and decent amount of notes)

Is it possible to sync multiple Exchange calendars (I have my own, plus a shared group calendar, and a third that is populated via an iCal feed)

Full folder support (including nested folders)?

Any support for categories?

Anything else I should know about the email client and Exchange? If the default email client is lacking, are there others available that are more fully featured?