Your first stop for answers to questions such as these should always be dvdcompare.net. I use it all the time.

I might get yelled at for suggesting it, but I think DVD Beaver ( www.dvdbeaver.com ) has a little bit of what you're looking for. Navigating the site is less than intuitive and reading white text on a black background makes for a great eye sore. Their library is somewhat limited too, but if you can find a movie you want on there, you'll be able to compare screenshots of different editions and their reviews will usually point out the differences between versions. At the end of each one, they usually put a little report card that points out which edition has the best Audio, Video, Extras, and Menus. Here is a Shaw Brother's review I found on there that you can take a look at: http://tinyurl.com/ydan3xt

And from what I've seen, Dragon Dynasty is a very reliable company. Their blu-ray transfers are never quite reference quality, but they always respect the source material and release movies in their original form.