Yes, that's nice.

I suspect that the features are not isolated to YMLP (YourMailingListProvider.com). Probably standard for Constant Contact, MailChimp and others.

I haven't found a less expensive alternative and it keeps my ISP happy since my number of subscribers exceed the ISP email terms of service for the # of emails per hour.

One thing is that if you ever go back to an automated newsletter app within zencart, you'll have to manually reconcile the unsubscribe list.