[Sussex] Groupware / Mailserver recomendation

[Diego Moore]

I need to replace our old mail server at work and am looking into options.

I'd love to build one from scratch (suse, gentoo, debain, anything!)
but I find myself having very little time and this is long due! So I'm
now looking into a COTS Groupware / Email server to run on Linux and
maybe even get commercial support for it. Someone mentioned
OpenExchange the other day and it looks like a very good option. Its
just slightly over my budget but the features are impressive.

So has anyone heard of any similar products or has any experience with
OpenExchange?

We use Outlook throughout, need IMAP, shared folders (mail, contacts &
calendars) and decent web based email. About 10 users but needs to
allow for expansion to 50+.

And something that can replace our old fastidious fax would be the
icing on the cake. I think our fax prints out more junk then we
receive spam!

Thanks in advanced,
Diego