better to use ruby to send email instead of rails context?

If my web app needs to send email notifications that are not time
sensitive (e.g. they can wait a few minutes), do you think it's better
for my web app to put the message on a queue or in the db for another
program (e.g. plain ruby) to load up and send the email? I know I can
still send them asynchronously by putting them on a queue and then
having a background process load up the rails context to send them, but
I don't know much about this and am wondering if I do that, would it be
that much more scalable to just have plain ruby or any other standalone
simple custom mailer program written in Java or whatever doing the
emailing?

If my web app needs to send email notifications that are not time
sensitive (e.g. they can wait a few minutes), do you think it's better
for my web app to put the message on a queue or in the db for another
program (e.g. plain ruby) to load up and send the email? I know I can
still send them asynchronously by putting them on a queue and then
having a background process load up the rails context to send them, but
I don't know much about this and am wondering if I do that, would it be
that much more scalable to just have plain ruby or any other standalone
simple custom mailer program written in Java or whatever doing the
emailing?

You may want to look at ar_mailer

http://blog.segment7.net/articles/2006/08/15/ar_mailer

-philip