I have a Schneider Comparon (read the spelling of that carefully) 150 mm f5.6, that I bought used. It is a truly wonderful lens. It's a 4 element design, optimized for low enlargement ratios (I think, from 1.5x to 4x, meaning 5x7 to 16x20 on a 4x5 negative). It is perfectly sharp. Schneider no longer makes these lenses. I'm NEVER selling this lens.
I bought an El Nikkor 135 mm solely because I could get a larger enlargement with the same enlarger setup, and might want to do so someday. (The lens was cheap on ebay.) But the El Nikkor is optimized for bigger enlargment ratios (I think 8x) so it shouldn't perform as well on smaller enlargements.
In practice, though, there is probably more visible difference between 2 specific samples of the same model lens than between 2 different focal lengths. Has to do with centering and aligning the optics, and manufacturing tolerances.
It would be easier to manufacture a lens with 4 elements than with 6, especially for centering.
Both 135 & 150 lenses are intended for 4x5, if of modern design. (The manufacturer's brochures will tell you the coverage and design enlargement ratio, if you can actually find a brochure.)