Version:           1.6.2 (using KDE 3.2.3, Gentoo)
Compiler:          gcc version 3.3.3 20040412 (Gentoo Linux 3.3.3-r6, ssp-3.3.2-2, pie-8.7.6)
OS:                Linux (i686) release 2.6.5-gentoo-r1

I use kmail for all my mailing activities. 
I connect to the company exchange server through its imap ssl interface, and it all works (except moving large sent mails to the sent items folder on the exchange server, which results in a lockup of the mailserver access. Another bug I suppose)

The thing that made me miss out on quite a few things is that kmail misses certain items that I search for. I search for sender (FROM) "veldhoen" it finds mails by that sender. These mails contain in the subject line "tijdsbesteding". I then try to find mails with "tijd" in the SUBJECT, and it does find some mails with words containing tijd in the SUBJECT but not those from veldhoen and others concerning the same subject. This is pretty bad, as I have a few thousand mails and I can't remember where all of them are as my brain is certainly not of superhuman quality. ;) 

So: I am searching on the imap server in the SUBJECT including subfolders and kmail misses quite a lot.

I certainly hope this is nog gonna go towards concluding that searching on Imap account does not work anyway...