Now that I have v3 and have fiddled with it for a couple of hours, I'd say it is not "the new Aperture." Yet.
The image adjustment tools are plenty competent and the AI Filters work very well. The user interface design was done well.
Transitioning from Library to Edit is not quite as fluid as Aperture's and you can't make adjustments to thumbnails as you could in Aperture. But the "mode switch," if there is one at all, is very smooth. The only jarring part is if you have a thumbnail selected and switch to editing, the thumbnail expands to full-screen and the Looks and Filmstrip Panels may appear (if you have things set that way).
Because the library features are so very new, they cover only the very basic ground. There are no keywords, virtual copies, stacks, nor IPTC tag editing. Those, other than stacks, are promised for the first seven months of 2019. So we'll have to see when they are released, and how well those features work. I'll be hoping for stacks (I really miss those).