I'm testing alternatives to the Gmail app on #Android, and right now #K9 looks like worthy opponent. With the help of #OpenKeychain it supports #PGP / #GPG and the overall look is reasonable. There do appear to be a couple of shortcoming - folder management is a little off; I have a handful of Inbox subfolders, but these aren't shown under the Inbox - all folders must be traversed in the folder list. Bulk folder management is unfortunately not possible either, which means that setting folder priority can take a long time. I'm using #Thunderbird 's "keep folder structure when archiving" feature, which creates a lot of structure that I don't need to see every day. Also, it would appear that this "keep structure" feature doesn't exist for K-9.
Any other suggestions for Android mail clients that support PGP? Paid is fine, as long as it's worth it :-)