The Mac email app leaves droppings all over my Gmail Drafts folders, is very slow at sending messages, and has no integration with my todo apps (Asana + something else). Search works perfectly though, and given that I have about 50,000 messages saved search has to be perfect for my email.
Problems with other apps:
- Mail Pilot: no Exchange support, todo within email not integrated to other apps
- Mailbox: no Exchange support, no todo integrations
- Airmail: bit clunky, can integrate with Things/Omni/Evernote but not Asana/Wunderlist etc., no iOS app
- CloudMagic: iOS app is almost perfect, great integrations and interface, but no Mac app