...Firefox I cannot take anymore. It opens and hangs for 30 seconds before it will react to any input whatsoever.
Yup. In double-quick time, Mozilla would seem to have managed to pretty much achieve their apparent(?) objective of killing off Firefox (well, that's the only explanation that I have been able to come up with that seems to make any sense of the otherwise inexplicable mess that they have been making of FF, anyway).
As potential alternatives to what used to be
a superb browser, I've been using Google Canary (64-bit Beta) for a while now, and Chromium. Both are pretty good, but Chromium seems to have been hobbled somewhat by the removal of Google APIs, or something.
I didn't know anything much about Slimjet until reading this thread, but the browser comparison table on http://www.slimjet.com/
is rather telling - assuming nobody's making unfair comparisons.
I rather liked SJ's "Stop eye irritation with automatic web page color inverting". It'd be worth trying for that alone, in my case.