Poorly designed mobile functionality. The app takes your standard pop up image and crops is into a small square, and then places the sign-up portion over top of it. It's fine if you use a plain or patterned background, but if you use specific images, it really looks bad. We, for instance, used a woman's face on our pop-up, but it cropped out for mobile and left an unpleasant part of her face under the sign-up form.
Disabled the app to try and contact customer support to turn off the mobile portion. They responded within a couple of days, but there's no way to turn off the mobile portion. As a last resort, tried to re-design the pop-up so it would work for both standard and mobile. It completely malfunctioned after re-enabling it and began appearing on every page, on every visit - even after I changed the cookie times. Basically, everytime I clicked to go to another page on the site, the pop-up activated. Very troublesome. Contacted customer support again and never heard anything back (this was about 2-3 wks ago). Removed the app from our Shopify store and would not recommend. If you do try it, hopefully you'll have better luck that we did.