Underwood's Mail is the new kid on the block, it seems to have arrived fairly recently. I got it to work but adding attachments to the emails did not work. One of the problems with Tor email providers is that they are often here today, gone tomorrow. Think of Sigaint, which was hugely popular at one stage but vanished suddenly for reasons that are still unclear. If you give a Tor only email address to someone as your main contact address, bear in mind that it may be unreliable or go offline without warning.