I gave it a try and here is what I learned:

1. It is a fun little program, I've always wanted something that could add buttons to my emails. I like the idea.
The execution has been difficult:
2. Photos will show up in some phones, and don't in others.
3. The design will work in some browsers and phones, and in some, the reply-all button will extend past the box and look might look funny to our customers.
4. You MUST take away all formatting if you copy and paste into the message box, because it won't show you that the formatting is all over the place until you send it. So it will look awesome in preview, and send different than the preview.
5. Right this moment, maybe the site is down, but I can't log in no matter which browser I use. I sent a campaign to test it this morning so I can't check in on it. Not sure what's going on there.