By request, here is a quick comparison of MAC's Retrospeck (Lustre finish/$14.50 for .05 oz) and Estee Lauder's Pure Color Eyeshadow in Glistening Gold (Metallic finish/$20 for .07 oz). These are very similar shades and I would go so far as to say they are almost interchangeable. The differences are subtle--as you can see in the photos Retrospeck is a tad warmer. They are both sheer and shimmery and useful for adding brightness and sparkle to an area, or as a quick all-over wash. I wore both today and didn't detect much of a difference in texture, pigmentation, or wear. Both have just a bit of fallout if not used over a base. At this point I wouldn't say I prefer one over the other, but maybe over time one will emerge as the winner!
Below left in sunlight and to the right, with flash: