Equivalents of all these can be presented the other way around against badly configured free software solutions.
Fortunately not microsoft sets open standard and have to conform to them or there will be microsoft only mail. And more fortunately not these admins.
OK response from exchange server getting properly my e-mail is enough proof that email was delivered to it. No attempts (including tcpdump trace) of sending e-mail from exchange serverr to me is too a proof of email not being delivered by it.
Yet fortunately it is really easy to fight it - EXPLAIN people.
Most people just don't know what they are doing wrong and not willingly want to make things more complicated. Simply explaining them is from my experience enough in 99% of cases. YES really it works but most people here never tried it!
As for latter - maybe it is possible to make exchange actually work, but statistics shows that it is not possible, or incredibly hard or people that are exchange administrators have no knowledge.
For any of my clients asking if exchange or outlook would be good solution i just recommend visiting any company that actually use it and ask average employee (not boss). This always work.
The other false statement is that such solution are designed for large scale businesses. The larger case the less chance it may work at all.
Seems i am the only one here that do not fear the truth. I don't risk being fired :) as i work for those that (most often) already got at least one of that "enterprise" solutions and wanted something that actually work.
And this is what i recommend to all of you.
I recommend ending this topic altogether, as it is not dovecot related at all - unless anyone will find a problem with Dovecot implementation of IMAP that is clearly not confirming to standards, and (possibly) affect microsoft outlook.
Highly unlikely but possible.
Dovecot is high performance IMAP server, but will not fix bad client software.