I have been using K9 and it was flawless. I liked the idea of seeing all my folders within Yahoo. The interface was nice, clean and easy. All of a sudden, it stopped syncing with the server...I delete mail from phone, it doesn't delete from server, then mail goes from read to unread, it shows 4 unread messages, I open it and there are 2. Really annoying since I am in my email constantly during the day. Not sure what caused this app to go nuts, but I need an alternative now.. Yes, I've taken it off and reinstalled several times.