Is LR4 worth purchasing if I already have Photoshop CS 5.5?
I don't need the anti malware software and would likely use the Sony software rarely.
The poster above is absolutely correct that your workflow speed will increase with LR, it's much more streamlined for basic edits (color correction, cropping, etc.). But even if that doesn't tempt you, I think you'd be well served to have the new raw conversion process version that comes with LR4 and is unavailable in CS 5.5. It's a big step forward, allowing much better highlight recovery and noise reduction. And yes, I'm a huge LR fanboy. It does 90% of the things I would have otherwise used PS for.