If your going to host your own email list software, the very first thing I would recommend is getting a unique IP address. In fact, get a few just to be safe.
The reason why I say that is because if your on a shared IP, any number of the websites that are on that shared IP could be practicing unethical technologies and it will only need to get that IP banned and your mail is not getting through.
If I had to use a paid one it would be
ListCast.com without fail.
They also have a relationship with Yahoo! where emails go through to the inbox rather than junk/bulk folders.
Yahoo! are notorious for not letting emails through.
Always use an opt-in, and make sure you have a privacy policy detailing that you will never share/sell email addresses.
Double opt-ins work but not as well.
KP