Who is using what MTA and why?

[Marc Perkel]

Just something I've been wondering about - when interfacing to spam 
assassin - who is using what MTA and why? Trying not to get into a 
religoius debate here - just trying to understand MTAs that I don't use.

For the record - I started with Sendmail (as we all did) and moved to 
exim and stayed with it. I'm hooked on the scripting abilities.

But - I've heard good things about Postfix, and Qmail - so I was 
wondering what it is that people like about their MTA choice.

And - how many fellow Exim'ers are out there?