I like the looks, too! Looks to me as if iPhoto will eventually be replaced by Photos (though I believe I remember the announcement was that it would not?) as it wraps most of its functionality and has a nicer look. Maybe makes sense to have Photos (lifestyle) and Aperture (professional) as two apps with a clear focus for each one.

I'm just missing some statement on how the performance is, especially since we all have like several hundred GBs or even TBs worth of pictures nowadays. It's only a preview with screenshots though...