Just finally got around to checking this out by looking at my house. It may vary by location, but this is definitely new imagery which is credited to DigitalGlobe whereas the old images wery copyrighted by the state of NJ.
It's also newer imagery, which was taken during the summer when the trees are full so you don't see as much of lakes, streams and trails. It clearly shows the driveway and landscaping changes made to my home by the previous owner ~4 years ago which were not on the older images. And it's true color imagery as opposed the the faux color infra red images from the State of NJ. I can see the red gravel in my driveway for example.
But it's also much lower resolution than the old images. Perhaps these are real satellite images instead of the NJ ariel photos? If I zoom all the way in with the new images I get the overlay saying no images are available where the old ones would let me go the full way.
Oh well, mixed blessing I guess. Haven't installed Google Earth on my new machine yet - does it have the same imagery? I'm also wondering if they intentionally "dumbed it down" to not show so much detail due to security/privacy concerns?