I don't post here very often, but I've been a member forever.
My fiance and I are annual passholders, and I'm a D23 member so we were so glad to get in to this preview event.
I have posted some pictures along with comments, on my Google+ page (feel free to add me to your circles!).
All in all, I have to say that I was sooo happy with the way everything turned out. I'm obviously a Disney nerd because I was actually more excited about the opening of Buena Vista Street than I was about Carsland!
Despite my issues with Carsland fitting the "California" theme (I'm still not sure we have mountains the ones surrounding ornament valley in California anywhere...), I really thought they did a great job with the land as a whole. Entering from Pacific Wharf and looking at those mountains that seemed to go on for miles was actually breathtaking.
We loved Radiator Springs Racers more for the interior scenes than the actual "racing", we loved the details scattered throughout the land. At times we found ourselves forgetting that we were actually still in DCA. It was crazy to think that California Screaming was just a few steps away.
One thing I don't think I'll end up liking much once the land is opened is the noise pollution in the Golden Vine area that will be caused by Mater's jamboree singing, but we'll see how that plays out.
Like I said, I was so excited about Buena Vista Street, and it certainly lived up to my expectations. The detail and theming there made me feel like I was in another place and time. What really impressed me was just how authentic everything there felt. With some minor exceptions in the black speakers that were simply set on some of the balconies without any attempt to disguise them, everything seemed perfect.
Even the Starbucks felt authentic, to some extent. To give you some background, I'm not a huge fan of out-of-place corporate sponsorship (I ran a "Keep Disney McFree" campaign back when McDonald's was moving in), and Starbucks is pretty out of place in an area dedicated to California in the 1920s. With that said, they did a good job of disguising it.
It's been a long time since I've actually been this excited about California Adventure... I'd say the last time I felt this way about it was when I was preparing for my first trip there, just after it had opened (before I knew better).
The new version of this park is a vast improvement and I can't wait to go back.