As a WYSIWYG editor it's very stable and popular.
It does make me wonder though, what happened to plain text emails? I had to abandon my favourite email client (mutt) purely because I received too many html emails. And I'm not just talking about marketing emails. Those I don't care about. I'm talking about work emails from colleagues.
Converting from HTML to text isn't that difficult, there are a number of open source libraries that'll do it. The harder problem is if someone sends you an email with a lot of images or where the layout of content is important, which is why people typically use HTML, it's much harder to map those aspects to plain text.
Every time I get a crappy text version of an email, I try to contact the company (via email or Twitter) to get them to care about text emails. Usually, I've received encouraging replies. It seems like marketing email services don't optimise text versions and companies don't even realise that. Probably because fewer people care about text versions.
I encourage you too, to send requests for better text emails if you care about this.
It'll be interesting to see how much adoption it gets because I don't think it's the solution most people really want. IMO, something simpler like a Markdown / Bootstrap for email is the real solution -- something that takes a simpler syntax or simple HTML and compiles it into "email compatible" HTML.
The thing that really sucks about email design is that you are stuck with HTML circa the early 2000s. An abstraction layer that took care of those annoying details seems like the real way to go. Curious what others think.
Then again, we have in-house editor similar to this (though less polished), and letting them use that is often also a disaster. We've found that making the templates more restrictive (give them places to type text, but not much more) tends to work best.
We build a lot of emails and we don't allow our clients to touch anything. It's something I hate dealing with on all levels but the ROI can be incredible for some business's.
This would be so nice in sending emails in an automated fashion.
Also, it is awesome to provide full functionality to test without jumping through signup hoops.
The preview window lacks a way to scroll the view (you can do it in the mobile mockup but the desktop view has no scrollbar and using keyboard to scroll down is unconvenient)
i'm making a small web-based smtp/imap client for an internal app and there's a lot of crappy email in mailboxes that i'd want to clean before dumping them into the browser for display.