Mail clients mostly look alike because they are constrained by the same protocols. The differences concentrate in three places.
Privacy
Does the app proxy remote images by default? Does it support OAuth rather than storing a password? Can it work without routing mail through the vendor’s servers? A client that fetches mail server-side has read access to everything.
Search
Fast local indexing beats server search for large mailboxes, but only if the index is on the device. Check how long a search takes across five years of mail, not five days.
Speed and habits
- Swipe actions that match how you triage.
- A unified inbox that does not merge unrelated accounts.
- Offline reading that actually works.
What to avoid
Clients that require an account with the client itself, and clients that cannot export settings. Both turn a convenience into a lock-in.
Bottom line: choose on privacy and search, then on whether the swipe gestures match your habits.
