Some users have recently had their accounts hijacked. It seems that the now defunct EVGA forums might have compromised your password there and seems many are using the same PW here. We would suggest you UPDATE YOUR PASSWORD and TURN ON 2FA for your account here to further secure it. None of the compromised accounts had 2FA turned on.
Once you have enabled 2FA, your account will be updated soon to show a badge, letting other members know that you use 2FA to protect your account. This should be beneficial for everyone that uses FSFT.
I've used Courier on Gentoo Linux in the past. They have a good setup document, and I found that to be quite helpful. Other documents exist on the Web for generic Linux setups.
I didn't find configuration or use to be difficult at all. I was quite pleased.
i snagged it because i wanted one written in c# with available source, and it's free.
i've had no problems with it, though be aware that clients sending certain search commands will probably not work as the IMAP FETCH command part of the server has been stubbed out for future implementation (it's currently at version 0.82, so it's not done).