Well the Library is much better. It's not really much better because of layout. It's just better because they provide you with more information in both Grid and Loupe view. I hate the RIGHT panel, and would rather not use it. However, the EXIF data I want to see is there. Sometimes, I just want to see the resolution of the image after cropping. Now, some of the data I want is just there, and if it's not there, I just go into Loupe view and there's more info from the Info Overlay than I need. 🙂
Oh, the one thing I was really upset about was the change to the Tone Settings in DEVELOP mode. They took away the brightness and contrast controls from the Tone Curve area, which I thought was useful, and they renamed things after I got used to the labels in Beta 3. Also, I didn't really understand the FILL LIGHT slider.
After one hour of playing with the DEVELOP mode, I think it is better. Oh, and now you can just drag the curve around from the graph itself!! 🙂 What's even more amazing is that now, you can put the mouse pointer over a part of the image (say the shirt that a person is wearing) and hit the UP-DOWN arrow keys on your keyboard, and it'll change the tone curve and adjust things accordingly. Absolutely fantastic editing feature!! 😱