The challenge with Hustle and all it's competitors is that it is site specific. I run a multisite and WPMUDev is supposed to be all about multisites but this plugin fails the ultimate test (in my humble opinion).
Let's say you have a main site with 10 sub.sites. In my case, each site addresses the same general audience (DIY) but the sub.sites target a specific sub-group of that audience (e.g., DIY for Kids). If someone subscribes to our newsletter via Hustle, the subscription is site specific. For example, if they subscribe on the DIY for Kids site, that subscription is for that site and the list is held by that site. That means that when I send a newsletter, I need to export every list, consolidate them to one, import them to the main site/list and then delete all the sub.site lists to avoid duplicates the next time I do the same! I send a newsletter every week so that's a LOT of work!
There needs to be an admin option to send all new subscriptions to the main site list, obviously with a flag showing which sub.site the subscription came from.
Am I the only one thinking this way?