Agreeable Gray vs Repose Gray
Two of the most popular Sherwin-Williams greiges, two points of LRV apart (60 vs 58). Agreeable Gray carries a bit more warmth and a faint violet cast in low light; Repose Gray reads slightly more neutral and gray-leaning in the same conditions.
Pick Agreeable Gray if the room already runs warm (a lot of natural wood, brass, or warm light) and you want a neutral that will not fight it.
Pick Repose Gray if you want something closer to true gray without going as cool as a blue-gray, especially in a room with mixed natural and artificial light.
How close are they?
Delta-E (perceptual color distance) between Agreeable Gray and Repose Gray is 1.5 (close enough that most eyes will not tell them apart on a wall). LRV runs 60 for Agreeable Gray versus 58 for Repose Gray, a 2-point gap.