LR3 does have some interesting features. The Develop module seems to process images quicker. Plus there are some improvements to Noise Reduction. Print module has some updates as well. Julieanne Kost has a video on the new features available at the adobe site.
Thing to bear in mind is that this is a public Beta and not everything is in this version that may be in the final release ( Please let there be soft proofing), This has been released for customer feedback and evaluation. Adobe go to great pains to tell people not to commit work to it, as things may change.