"BEWARE: this release is not compatible with Tiger. This version introduces many fixes, notably for SSA decoding, v4l2, MacOS interface, ogg/theora, x264 modules and security issues. It also introduces the port to 64bits for Mac OS platform and 2 new languages (Kazakh and Croatian)."
I'm not sure what "Mac OS interface" fixes were included (the app looks the same to me, but perhaps it refers to minor fixes rather than major changes), but two things probably jumped out to you: the first is that the app is not compatible with Tiger, although this is not new with 1.0.2 (downloads for older versions of Mac OS X are still available).
The second is the "big" news: VLC is now 64-bit. Again, this is not a change that end-users are likely to notice, but if you have been following news about Snow Leopard you know that 64-bit has gotten a lot of emphasis, and it's great to see VLC is keeping up.
Someone recently asked why I would use VLC on the Mac when I had QuickTime Player or Apple's built-in DVD app. My answer was two-fold and simple: I use it because when I want to watch DVDs I can press command+D (to open the DVD), press enter, and VLC automatically takes me to the main menu of the DVD, skipping all the ads and previews and other nonsense that the movie companies try to force you to watch every single time you put in a DVD. The other big reason I use VLC is because is has an option (under the "Video" menu item) called "Float on Top" which, as you would expect, keeps the video window above other windows. I was disappointed to see that even QuickTime Player X does not offer a similar feature.
VLC may not be beautiful to look at, and its advanced preferences are enough to make a normal person go cross-eyed with confusion, but it is a video playback workhorse, especially when paired with the US$3 iPhone remote control app (iTunes link).