Let me try to summarize this up in my final reply on the matter.

First, to the point that "3 or 4 times a year is not that much": At the moment I have in the neighborhood of a hundred active clients or so, many of them businesses. Having this particular issue come up with that small of an active client base is, to me, too much. Some of these businesses are research firms that are regularly sending data to outside contractors on tight deadlines and insurance companies trying to shuffle paperwork, contracts, and other agreements around.

Which brings me to my second point: we may simply have different ideas of what constitutes proper customer service. I believe, strongly, that it is totally unacceptable to have even one of my clients miss a deadline or experience even a relatively minor issue in their business because a mail server somewhere incorrectly flagged a message as spam, especially when that could easily have been avoided.

If the RBLs were managed more carefully, if there was accountability, if they had any incentive or desire whatsoever to go to great lengths to minimize the impacts on innocent users, then I would very likely have a different opinion of them. But, they do not. Vixie has been quite public in his very low opinion of spending any effort at all in minimizing the impact on innocent users. [1] We're talking about handing over massive amounts of network influence to a guy who would be willing to blackhole huge swaths of the internet just to decrease his personal spam volume by one or two messages per month. Is that really the internet you would like to be operating in? It's not the kind I want, for sure.

I don't see how the SpamAssassin issue you mentioned -- which I had to deal with also, albeit on a much much smaller scale -- makes RBLs any more or less trouble than they're worth. Either they're worth it, or they're not. I don't think they are, because I don't think they work well enough as a sole indicator of spammyness, and I think they have too many false positives. When they do have false positives, that translates to real, serious problems for real people.

Also, we're approaching this argument from two completely different environments. It's clear when you enumerate the list of problems that you have to spend time on that you're focusing mostly on things which bother a system administrator -- software updates and that sort of thing. However, I'm focusing on problems which bother users -- business owners, employees, individuals, professionals -- and while they don't tend to be impacted directly by things like software updates or slow mailing lists, they are directly impacted by things like all of their email to a contractor with whom they've had a longstanding relationship suddenly getting bounced by an erroneous RBL entry.

And, regardless of your experience with it, I'm telling you that it happens, and if my experience counts for anything at all, then it happens way too much.

[1]: For one quick example: http://www.mail-archive.com/nanog@merit.edu/msg23942.html

edit: For another example, http://www.mail-archive.com/nanog@merit.edu/msg04890.html and Vixie's reply ("zeal must become the norm.") at http://www.mail-archive.com/nanog@merit.edu/msg04904.html -- this is simply fundamentalism, and it will not lead to a healthy internet.

edit2: and more: http://www.networkworld.com/research/2001/0910feat.html ... ok, I'll quit now. Point is, there simply isn't grounds for saying, "it's not a problem."

edit3: http://www.infoworld.com/d/security-central/why-i-hate-rbls-...