It appears that it'll replace exim as the running daemon, and will then inject all mail through command line incantations of the sendmail alias of exim.
It should work, but anything depending on finding exim running will fail. For example, unless you remove the check, DA will continually tell you that exim is down and can't be restarted.
Unanswered questions (the site may have the answer; I didn't study it):
1) does it support the authenticated submission port or will you have to run the exim daemon on that port if you want to use it?
2) does it properly handle POP before SMTP?
Without some kind of authentication none of your users will be abe to use it to send mail.
You're on your own; if you need any support you'll have to find it from the folk who created it and their support channels.
Jeff