I have used Thunderbird since it was integral to Netscape (Yes, I’m that old), and have been very happy with the product. I have used K-9 mail since moving to an Android phone from my Blackberry years ago, and I’ve been satisfied, but a little disappointed in the development. I’ve been hoping for an Android TBird app for a long time. Hopefully, this will be the best of both. My only sad thought is that the K-9 logo will go away. Where is Sarah and the Doctor when you need them? SAVE THE LOGO!!!