Email - PHPmailer

You cannot do this in PHPRunner.
I'm probably missing something but what is the benefit of this? Making users enter their email login and password to send the same email you can send on your own?

From what I understand when you put a from email address in, it displays from @test.com but is really using your mail host. When You I have sent emails in to companies like universities etc which have really good anti spam settings these emails just do not get though (not even in to the trash folder). The way around this that I found in the past was to use the PHPmailer function and add the username, password etc.
For me users would not add their details every time, when I set up a site I would include all the details in a site set up then the emails would be automatic.
For me this is an issue as i need the confirmation emails to be delivered. Can I use Phpmailer or will that interfere with the current phprunner mailer set up.
Regards
Richard

Yes, all emails are sent through the same SMTP server no matter what FROM address you use. However, to send an email from someone else's server yo need to have SMTP server address, username, password and, sometimes, SMTP port. Besides that, email address is the most important thing in a modern Internet world and giving out your email password is like giving your wallet and house keys to strangers.
You can have better luck using a trusted SMTP email service like SendGrid or Amazon SES. We use SendGrid to send out our newsletters.