Thinking about dropping Gmail, but it's killer feature is its excellent search capabilities. Looking at OSS solutions, none seem to have search that even comes close.
I can usually dig up a several year old email in a few seconds, including time to fiddle with the query to get what I'm looking for (so multiple searches completed in, like, 5 seconds.) That's hard to beat .
@teleclimber If you don't mind maintaining your local index (and fair enough if you do mind), then I would imagine any of the Xapian based solutions like notmuch or mu would match GMail in terms of retrieval time. The other stuff about effective searching is much harder to quantify, but e.g. support for phrase search is also similar.
Disclaimer: I maintain and use notmuch, and barely use GMail.
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