Okay, so I have some sort of... fake-o impressions for those curious.
Firstly, the patch process SUCKS ASS. The patcher warns it could take up to 2 hours for a slower system to process all the upgrades and changes to files, and they aren't kidding. It was probably around that for me, and my system is still respectable. So that sucked. Much easier to just get the enhanced edition and install straight away, though it certainly wasn't the end of the world... and free is free! I did have an issue because my copy of the game wasn't registered, which I could have sworn I'd done, but it was a simple thing to get it going and for the patch to authenticate my copy and give me the new stuff for free. I think the problem was that I'd tied my copy of the game to my account on the Witcher forums, which gave you some bonuses and stuff at one point, but I never actually registered. I think.
Anyway. Beyond that, I can say officially that the patch does absolutely nothing to alleviate the game's shitty beginning. I think in our original Witcher thread I detailed some of my initial fears and disappointments with the game, and they're all intact on this second run. The opening segments perform quite badly from a technical standpoint (more so than areas after that, which in my experience have all played much more smoothly), the opening tutorial stuff is a little on the dull side, and the weird jump from the prologue to chapter 1 is still totally jarring and leaves you feeling like you missed something, including the first conversation you have with the chick, which remains stilted and unintentionally funny as she goes on talking to you about how concerned she is for the boy, who writhes around in pain the whole time just behind her. Now these were fundamental problems with the game from the start, so I wasn't expecting them to be fixed... but I was kinda' hoping against hope. And to anyone that hasn't played the game yet and wants to try it: DON'T JUDGE THE GAME BEFORE GETTING BEYOND THE BEGINNING OF CHAPTER ONE! Seriously, I was just flat-out disappointed with the game at that point on my first run, and it wasn't until a bit later that I realized how brilliant a game it truly is. So... yeah. Just wanted to get that out of the way. This isn't like Knights of the Old Republic either, where the entire opening planet is just boring as fuck. The boring part of the game is very short and you can get through it probably in an hour or so.
So as far as the little bit of new stuff I've been able to see so far... it's very nice! The game does seem to perform better, though it's still a little inconsistent and certainly imperfect on my machine, but generally things seem to be a step up from what they were before. And some of the new dialogue that I've seen works very nicely in the sense that it doesn't stick out, it seems to fit naturally into the context of what was already there, so that's pretty cool. There isn't this old stuff/new stuff dynamic popping in and out all the time to distract you.
Anyway, initial impressions are positive. Fundamentally you're still playing the same game, of course, but it looks like the little touches are going to make some of the rough spots a lot more palatable. I'll post some "real" impressions once I get a little more time in.