MAC Blush Pink is a slightly warm-toned, very light peach with a semi-matte finish. It is a limited edition blush that retails for $35.50 and contains 0.35 oz.
MAC Blush Pink High-Light Powder ($32.00 for 0.35 oz.) is described as a "light pink with silver." It's a light, pink-peach with a semi-matte finish. The silver is an over-spray that will disappear after one use. NARS Paloma Highlight (P) is lighter. NARS Sex Appeal (P, $29.00) is slightly darker. Get comparison swatches / compare dupes side-by-side.
FURTHER READING: Formula Overview, which is a detailed review of the range as a whole.