I did a full rollout to 2 large companies saying there is a better alternative to MS products at little or no cost blah blah. Barely finnished removing MS Office and Exchange then users all start complaining. Mostly about the right click and Send To not working or not being able to send mails from Pastel and the such likes.
I'm not having to re-install Office at my own cost and with the upgrade just to keep one of the clients.
I too saw the default mail handler when I installed the test PC's etc but never though to test it as its there and the rest of the Zimbra suite seems so polished.