Okay, writing this as I read...

(1) This is long, long overdue. I'm glad WOTC finally got their act together.

(2) This is overall rather sloppy. I notice several spots where the errata needs errata, such as Arcane Initiate, Mnemonic Staff, Quicksilver Stance, and Unicorn's Touch.

(3) Several loopholes (that I expect most DMs wouldn't allow anyway due to dubious interpretations) have been removed, such as Vengeful Weapon, Rod of Reaving, Mnemonic Staff, Swordmages wielding 2H weapons, and Dual Weapons in general. This is a good thing.

(4) Most importantly, many of the ubercombos, and the items or powers that everybody wanted regardless of class, are gone. Several of them have been nerfed into oblivion and are mostly useless now, others have a sensible power level. This includes Bloodclaw & Reckless, Cloak of Distortion, Quicksilver and Spitting Cobra, Hero of Faith, and the Riding Lizard.

(5) Some things haven't changed. Bloodiron is still uber, and Bolstering Blood is now even more explicit that it works on every square of Blood Pulse. I've seen lots of nerfs to saving throw penalties, but I believe there's still enough of them to make a viable stunlock wizard. I'll have to check that, though.

(6) Some things that really weren't overpowered have now been nerfed into oblivion. This includes Blastpatch and Storm Pillars.

(7) Some things that didn't work as printed, now do. In particular, Eldritch Strike.

Oh yeah, and Needlefang Drakes have a much-needed nerf. Overall, this is a much-needed fix, and addresses 90% of all the little things that people have been shouting about for months.

Does it strike anyone as odd that there's fifty-eight pages of errata now? Time for 4.5, perhaps?