Meaningful innovations

Lightroom is with me since the version 2 in use, because it best covers I think the workflow for RAW shooting and support. Since then, I'll do 95% of photographic works with the program, the use of Photoshop is hardly necessary for me because I chiefly operate on image improvement, but no complex installations or the like.

I switched on the following grounds on the Version 3:
+ New possibilities of image processing, such as lens correction (automatic): Transform / Vignette / fringing etc.
(Just correcting converging lines or distortions directly in LR is very helpful as had with me else PS ran. If one possesses is already included in the LR-specification list lens, an automatic correction is possible with a single click. New profiles for their own, not prescribed lenses can also be applied) but
+ New denoising
(Which is much more efficient than the old - and very important especially for modern cameras with ISO 3200 + is)
+ Watermark
(Very useful for all with its own photo website because LR2 only a copyright simple insertion allowed at the edge, however, the watermark now designed in LR3 themselves and can be placed freely)
+ Management by camera-video files
(Which could not even recognize LR2)

From the advertised speed increase I certainly have not noticed much, but I had in that respect and no problems with LR, probably due to faster disk, 6GB of RAM and 64bit Windows.

Conclusion: Meaningful innovations, no weaknesses compared to its predecessor, acceptable upgrade price -> buy recommendation!