Easy to understand and use (as the app name implies). I didn't get far though. Never tried it in my store since there is no way to choose a decent font for the (only) two text zones of the popup without getting the paid version (seems a bit steep if you only need a decently formatted popup and nothing more).
No way to create layers (?), so I guess this tool seems to be geared towards beginners more than advanced users. Jutuno offers a full-featured free version, so really basic functions (like a limited fonts choice!) need to be included in this app too in order to be competitive. I'd be more inclined to pay for a service once I've used it for a couple of months and think it's solid enough for use in my store. I can't use this one for two months because it lacks too much features in it's free version.
I'll stay with Justuno... although it's ridiculously complicated to use sometimes.
Tough crowd I know... but that's the Internet these days. ;)