I'm surprised the LPL doesn't allow for alignment, but if the alignment is good that's all that matters. If it is not good, then you have to find a way to correct it.
Originally Posted by ymc226
As other have said, the Nikkor 50 f2.8 is an excellent lens, as long as you are meaning the newer version (which is not really that new) with illuminated f stops (called 50mm F2.8N as ath mentioned). I used the older version for many years, not realizing that the later one was a redesign with much improved performance.
Related to that is using the optimum apertures. Ctein found f4 to be optimum, but that is very demanding of alignment and negative flatness. I generally use f5.6 to 6.3. With small prints I'll stop down to f8 if I have to. With a good 50mm lens, stopping down more than shows a perceptible loss of sharpness, and the larger the print, the more it matters.
The 50 f2.8 Nikkor is optimized for 8x, and Nikon recommended its usable range as 2x-20x, so you are well within its designed magnification range. I'm happy with 16x20's with this lens. If that was my standard size, or I regularly printed larger, I might look into a lens optimized for higher magnification, but I have no complaints with this one.
35mm can look great when everything is spot on, but it is not very forgiving.
The two Saunders enlargers I own (670 vcce and 4550xl) both had to be shimmed to be aligned, so don't believe the "it is aligned at the factory" bs. Do yourself a favor and make sure. Without your enlarger being aligned it won't matter what lens you use.
Alignment is much more important than the lens.
The difference in a good enlarger lens and an APO is very small. As already said alignment is much more important.