> - An archive folder that works well with the archive functionality in Mail.app and other clients.

I switched to Fastmail a few weeks ago and am as pleased with it as you. Just one question though - I can't find a way to recreate the "All Mail" folder from Gmail, where you would delete mail in Mail.app and it would end up in "All Mail". It ends up in Trash instead. Same with my iPhone - if I delete a message there, it goes to Trash, not "All Mail" like it used to with Gmail. Were you able to get this to work?