Haven't noticed too much discussion, and maybe this book's gotten kinda lost in the shuffle. I got mine from amazon yesterday and, though I haven't read all of it (partly due to my happening upon an AOTC spoiler under Ki-Adi's bio and not wanting to spoil the movie further), it looks awesome.
The art kicks the living doodoo out of the art in the previous edition. Even Xizor and Dash Rendar look better than the pig terds we all know them to be. Corran and Mara look incredible. And in color!
I noticed that the little discrepancy about Greedo (how he could be a youngun' in ANH and be beaten up by Anakin in Mos Espa) is addressed, as is the origin of that nutty "Jaster Mereel" moniker Boba Fett's been known to use. And there's also a tiny bit about the whereabouts of Boba, Bib Fortuna, and Kyle Katarn during the NJO, as well as the sad news of Mon Mothma's passing.
And best of all, since it doesn't include folks like Het N'kik, Gartogg, Kneesa, and Davin Felth, the old one isn't completely obsolete! I hope any updates to the other Essential Guides are the same way.