MAC Glow With It is a moderately warm-toned, medium-dark brown with a satin finish. It is a permanent highlighter that retails for $37.00 and contains 0.31 oz.
MAC Glow With It Extra Dimension Skinfinish ($33.00 for 0.31 oz.) is a muted, rosy brown with fine, golden shimmer. There was an almost plummy tone to it when blended out, but it seemed more brown than plum overall. For a Skinfinish, it actually had less shimmer--and finer shimmer at that--compared to the majority of Skinfinishes I've tried. It absolutely still gave a glow to the skin, but it was easier to be heavy-handed and not worry about emphasizing my skin's natural texture. It had great color payoff with a very smooth, soft, and blendable texture; it felt like the perfect balance between soft and firm where it was easy to grab product with a brush but not at all dusty in the pan. The color wore well for eight and a half hours on me.
The Extra Dimension Skinfinish formula is supposed to give "the perfect glow to the skin" with a "creamy powder formula" that wears for "10 hours." It's a powder highlighter that I'd describe as a moderate to intense highlighter, and they come in varying hues with some that might work as highlighting blushes/bronzers are on some skin tones and true highlighters on other skin tones. In general, the formula is very pigmented, blendable, and wears around eight hours on me.
FURTHER READING: Formula Overview, which is a detailed review of the range as a whole.
A liquid-powder highlighter with prismatic reflections, designed to highlight and brighten your face for an intense, iridescent metallic finish. The creamy powder formula lasts up to ten hours.