The problem with all email designers is they only work if the recipient is happy to accept html, css, images and links.
I use Thunderbird and have images turned off by default. Same on my iPhone. This means your carefully designed email doesn't work they way you want it.
The very best emails are simple with the absolute minimum of styling and imagery. If you do this then it doesn't need to be responsive.
Thanks for the lesson in Email Marketing... I'm well aware of the limitations. A carefully designed email will work regardless of images being turned on or off.
That said, I'm always surprised that people still turn them off by default, we're not on dial-up anymore, why bother?
I'll probably continue doing it the way that I've always done it, I just saw the software and it got me asking if there was a better way.