+0.5 for Sendy. I've been using it for http://www.tittietime.com quite successfully for 2+ years now.

There have been a couple of bugs that caused me to have to dig into the source code - which as others have stated, is a mess. Though I suspect its been purposely obfuscated to prevent pirating.

If you ever wonder what's going on in functions.php, I've unwound it a bit - you can see its making a phone home:

https://gist.github.com/anonymous/cb21dfc35e1d4b74e136ebc694...