I have now played with LR4 and especially on some pictures that I had trouble with in LR3. That is often pictures with mixed light and extreme DR (still from one RAW file). I used for a long time a sort of tone mapping in LR3 using recovery and fill light and compensated with the tone curve and brightness. And leveling out the extremes of light using graduated filters (sometimes a number of them) and brushes. Sometimes I got results that pleased me and sometimes I resorted to Photoshop to finish it up. I have now gone through several of the pictures in LR4 and I must say such an approach works a LOT better. Especially the shadows slider works really well and with much less side effects than fill light. What I also really like is the ability to brush in white balance like a higher white balance value in shadow areas (and btw. noise reduction selectively). WOW, I'm impressed!
After reading what you wrote above, I decided to download LR4Beta and give it a try ...
... yes, it is vastly superior to LR3 when it comes to dealing with shadows and highlights in images with large DR.
