it's just that your original post wasn't accurate in describing qmail, nor did it dismiss it on technical grounds.
I'm still not getting what I misstated here. I said
qmail is very neat, but is not OSS and has config files scattered all over the place and is headed by DJB.
1. qmail is neat: check.
2. has config files scattered all over the place: somewhat. You say they're in /var/qmail. I still say they're scattered because they're not in one file. We agree to disagree
3. Is headed by DJB: I've given you my arguments against DJB. If you still feel DJB's conduct is acceptible, so be it.
All this aside, thanks for the info on VERP. It seems that Postfix does do VERP but only when requested (either through sendmail args, SMTP XARGS command, or QMQP sender address). I can't say which approach is better for large mailing lists, but I have anecdotal evidence that qmail's approach is paranoid (in a good way), but may not be cost effective. qmail doesn't give you an option on which approach you take, postfix does. You prefer not to have an option to tweak the behavior of your mailer, I do.
The config files for postfix are very straightforward IMHO. Each parameter is defined like
<PARAMNAME> = <VALUE>
The syntax of the file is documented in great detail, and the man page for each daemon in postfix documents the params it uses. To me at least, it seems to be the right way to do it as in postfix you choose what daemons you're dealing with and only RTFM for those daemons.