***This review is specifically for the design quality of the admin side of the app, not the front end.***
This plugin works, and I have no problem implementing it on my site, but it was very frustrating when I first installed it. The features are not obvious and making changes is not intuitive; that definitely needs some work. It took me a while to figure out a basic "text with call-to-action" button configuration. Once I played around with it things made sense, but for a less-experienced web user/designer then it may cause frustration. It has nothing to do with my theme or CSS, but the admin design of the app.
Also, a few other frustrations that I would love to be addressed:
• Adding a background image works, but the image does not scale to the browser. I tried a 2000px-wide image and it "repeated" the image across the top (looked awful). So then I tried a 5000 px-wide image and it went off of the page (cropped it down). It didn't matter what size my browser was (using Safari fwiw). There is nothing on the plugin or documentation that gives a pixel resolution to make the image fit the width, which would be ideal. Either that, or it should have the image scale to fit the browser width, regardless of image size. This IS supposed to be a "responsive", app, right?
• The Mailchimp option does not allow you to add users directly to groups after signing up. Maybe I'm wrong about this, but I couldn't find any way to do it. Groups are listed in the Mailchimp settings, but when you add an opt-in there is no option to add signups directly to a group. Other apps I use with the Mailchimp API manage to make this work, and it would be great if it worked in the notification bar as well.