I've reread his posts, and I do see his concerns are somewhat different. My concern is, I think, more universal and thus more important.
zD insists on offline use, insists on downloading the entirety of every email from every server folder. Every other IMAP client, that I'm aware of, downloads only the Inbox headers, and nothing else, when you add an account. With other clients, you have to change the default settings to go to offline mode. You'd think zD would at least sync the Inbox first, but that does not appear to be the case. If I wanted to use zD as a client, my best option would be to add the account at bedtime, then let it churn away for hours while I snoozed. This is not a recipe for glowing user reviews.