5D MkII looks even better in LR4...

Speed seems the same as LR3 in my Win7-64 machine.

As others have already pointed out the W & B point settings are much improved in "Process 2012." It's most noticeable in the initial highlight rendering.

Fine structures and NR also seem to be better and the Detail slider has a much stronger effect now and acts in a similar way to some 3rd party (e.g. Nik) "Local contrast" filters...useful in some cases, not so much in others.

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