As much as I like Firefox, beginning with version 29 and just now version 30, tabs only show up on top — whereas in previous versions one could enable or disable that feature.
(I've already lodged a complaint with Mozilla, but I'm not sanguine that anything will come of it.)

If there is a (surreptitious) way of achieving tabs below the navigation (and bookmark) toolbar in the versions since v.28, I'd like to know how (such as a toggle in about:config).

Check out the user comments on this topic here.

Many thanks. MacInTouch is not a place I'd normally check.

Bottom line: I think I'll just hang tight with Firefox 28, unless and until Mozilla smartens up and reverts to the status quo ante with its newer versions – especially since there are a number of other issues affecting Mac OS X negatively which still remain unresolved/unfixed.

Firefox 32 has just arrived on the scene.
It appears that many of the Mac OS X difficulties have been resolved/fixed.
However, the tabs on top remains an integral non-option (under View) — although there is an Add-on extension "Tabs on Bottom" which corrects for this.
Coincidentally, "Tabs on Bottom" also allows for the title of the page to be displayed at the top of the window (which tabs on top precluded).
So I've decided to try out Firefox 32 (updated from version 28) together with the Add-on and see how it goes.

Two changes have really improved Firefox 32's (vs 28's) performance:
• New HTTP cache provides improved performance including crash recovery
• Performance improvements to Password Manager and Add-on Manager

Barring any difficulties appearing in future, I think I'll keep it.