Much has been written on many forums about travails caused by SEF's. What's the distillate of all this brewer's foam? Is there a bumper sticker answer, or is this a nightmare that awaits all Joomla publishers who would rather have their links be in plain language, rather than a geekspeak query?

Here's my own rules:

1) Don't enable SEF until the last minute
2) Create a menu link (even in an unpublished 'dummy' menu) for each item on the site. Otherwise you get 'K2' or 'Component' or other strangeness in your URLs.

If you can't do no. 2, because of the volume of items on your site you need to either live with the funny URLs or get a 3rd party SEF extension.

And i've been reading of problems w 3rd part SEF extensions... this will give me a migraine...

If you don't have hundreds of items oon your site, I would stick to the core SEF personally.

Just follow rule 2!

there are over a hundred... though a lot are now unpublished / archived

Your call.

well, it 'failed' but not for the usual reasons... so many people have bookmarked the unintelligible URL's that SEF broke their bookmarks. i wish the joomla people would add a lookup table so both url's will work....

You can add 301 re-direct rules to .htaccess that will update peoples old bookmarks.

Just Google fro 301 permanent re-direct.