I have not and will not use this application. I understand that many applications need administrative access in order to run properly, and I have several running (including Little Snitch, which has installs its own kernel module.)
However, I refuse to use a program that does not explain WHY it needs that level of permission and what it will do to my system once that authentication's been given.
This appears on the surface to be a normal, user-level application. Other mail notification programs do not need this level of permission and I find it hard to understand how the developer could justify this.