I do an A/B test on the video, but you have to wear headphones if you really want to hear the difference between the noise floors on the two units. If you can't hear it here because of Amazon's draconian compression, search "Zoom H4nPRO vs H4nSP" on YT for a higher resolution version of this video.
PS - Writing reviews has become an accidental hobby for me, and it always makes my day to know that people find my reviews helpful (and if not, why.) Also, if you have any questions, clarifications, or comments please feel free to leave a comment below. I usually respond pretty quickly and almost always within 24 hours.