I have been using their services and they have been pretty kind answering a lot of questions and fixing as fast as possible a couple of issues I opened on their GitHub repository; they had a feature that redirected you to their .onion web site if the server thought that you were using Tor and my Firefox profile matched their rules so they added a window asking you if you want to be redirected. Really useful if you are using Tor, it’s a real hassle to search for the correct URL to enter a website more securely.
I think they are missing the STARTTLS listing by the EFF to meet PTio criteria, and therefore to be listed. I will fill an issue about the non encrypted images, I noticed that, too.
Their webmail works perfect for me, it doesn’t take more than a regular browser to open an e-mail. Which security level are you using?