I've been looking over MailChimp and GetResponse. While I could host my own mailing list or AR, I prefer not to. Being a web developer it's something that's quite easy to install and setup. The problem is ensuring delivery. Some hosts, especially on shared hosting, may limit outgoing email. This can become an issue if you're trying to send a message out to 2,000 subscribers. Sure, you could set it up in batches to send x-number of emails within a time frame, however, I'd rather just go with a remotely hosted solution.
I was looking at MailChimp due to the free option. I'm just getting off my butt so I don't have a mailing list. Therefore, I doubt I'd reach the threshhold very soon. If I would it'd be great though.
What got me thinking of GetResponse is the integration it has with JVZoo. According to JVZoo, you can have your buyers instantly added to your mailing list. GetResponse does offer a 30-day free trial.