I currently use APO Rodenstocks for all my B&W enlarging. However I can't say I see any difference in image quality vs the non-APO Nikkors I used before I got my new enlarger. Perhaps this is because I don't make very large prints, but in general I doubt there is much of a difference. The plus side with the APO vs the lenses I used before, is that if you need to open up a bit wider, the ones I have are essentially fully corrected one stop down from wide open, so if I needed to, I could use f4 on my 50mm and get full quality. I've never personally needed that, but it could be useful for some people.
On the subject of Rodenstock vs Schneider, don't waste your time. They're of equal quality and indistinguishable.
+1 to all of the above- my experience is exactly the same.