LR4 Issue: Library View

I am seeing a huge difference between my RAW files and the the processed JPEGs. I never noticed this in LR3 and I have not changed any settings. I previewed the same JPEG in Picasa as well as the Preview picture viewer on my Mac and they look just like the RAW file. Is anyone else having this problem??? If so, any idea on how to fix it?

EDIT:

The main difference is that the JPEG looks WAY too contrasty and is showing nasty halos

Example Screen Shots:

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Attachment 723

I found the problem. It was double processing the JPEGs. Every time I exported it was applying the same treatment so that it was stacking upon itself and getting strong and stronger. I never had this issue with LR3 but at least now I know how to resolve it.