I've actually found Wufoo + Gmail to be the simplest way to handle e-mails. Use a Wufoo form to collect user info, then export the data to csv and import the file into a Gmail group. I haven't done anything terribly advanced (I just notify a list when a new article is posted) -- but it works for me.
I'm the developer of Direct Mail, if you have any questions. We have several customers using Direct Mail with SendGrid and they seem to be very happy with the setup.
Thanks for the reply, jhammer. I'll get the Pro version before the 50% off ends and I'll try by myself.
Thanks Marcus - I've added a couple of others in a comment.
wish it distinguished free from paid.
I think most feature a "free trial" at least. I'll see about adding more info to pricing, but was more concerned with coming up with maintaining a list I could share with clients.