I just found out about eM Client - E-mail Client with Calendar

Apparently a CalDAV + IMAP client, it seems like it could be a good alternative to Outlook for Windows people who want a "normal" client app instead Zimbra Web Client/Zimbra Desktop. (I suppose Mulberry would be another option but the lack of recent updates is a bit off-putting. On top of that, I never hear about anyone using it in a business context, but maybe I don't get around enough.)

Does anyone have any experience with eM client and Zimbra?