I emailed the developer regarding a problem I was experiencing with the dates of certain emails (eg. 1904 appearing instead of 2004) and he replied within the hour, and attached an updated version of the app!

For the functionality this program offers, and the speed with which it performs (I have a 16000+ message database, 2.7 GB) I am very happy. Mail app is also running much better now I've cleaned it out.