I've been mostly happy with the mail setup i documented some time ago, but i never was fully convinced by offlineimap, it was often slow, sometime blocking, and felt a bit unreliable. Last time i went out looking for a replacement, there wasn't much of them around, and although i had read a bit about mbsync, it didn't seem nearly as commonly used as offlineimap, the voices praising it were few.
Discussing my issues with offlineimap at work the other day, i discovered that a co-worker had been using mbsync for his setup for years, and seemed to have zero issues with it. So i decided to give it a whirl.
I based my configuration on information found in the arch linux wiki which is often a very nice source of information, even for users of other distributions, especially for users of uncommonly used, nerdy, pieces of software. I directly pointed my configuration to my existing Maildir, and after a few runs (the first one seemed to chock a bit on the number of mails to sync), it went well and have been running very reliably since.
I'm not running it into a crontab yet, i'm just keeping a terminal next to the mutt one, with a simple script like:
while true; do; sleep 10m mbsync -a; date done
Which allows me to see when was the last sync, and what actually happens during the sync. I must say i'm really happy i don't have to go forward and code my own IMAP synchronization tool, that would probably have been a very pointy experience.