I received it yesterday.
1) It's thinner than I thought it would be.
2) The 22 page star atlases in the front of each of the separate volumes are gone.
3) The index tabs at the edges of the pages are gone!!
4) The Common Names list is no larger than before.
5) The transparent overlays are gone!!!!!!!
Essentially, it's the same. If any refinement of positions took place, it isn't mentioned. The only thing I'll really miss is the Edge-of-Page tabs.
It's definitely more cost effective that getting the 2-volume set.
But no tabs? No transparencies?
I wish they had kept the tabs and the 22 page atlas at the front. The one volume all-sky version is really more cost effective only if you don't care about the overlays, which are now $15 a la carte. IIRC, the two volumes with overlays included were $100 total; now, the one volume all-sky version plus overlays totals $85. Personally, I'd rather pay the extra $15 and get the tabs and the 22 page atlas at the front, though unfortunately that's no longer an option.