I went to check out this foundation today at my local Mac. They were sold out of nearly all of the lighter shades. I'm typically NC15 to NC20, and the SA matched me to NW25. She made up a little sample. I knew that this runs a little different than other MAC shades so I really didn't question her. Also, this shade actually did look fine (not too cool/dark) when I first applied it. Now, it is quite a bit darker/warmer than my neck. This could be a color-shift oxidization. It happened quickly--within the first hour.
I've been wearing it for several hours so far. I applied two very, very thin layers, and achieved full coverage easily. This really hides everything.
I think I've over-applied it, because it's highlighting my pores and looks a bit artificial.
I have enough sample left over to give it another try tomorrow with sheerer coverage.
It's so humid today--this foundation does allows sweat to 'bead up.' The foundation doesn't seem to move under it at all---still holding strong. Because some of my summer is going to be spent in hot/humid areas, I'm sort of curious to keep trying with this foundation to see if I can make it work. But I'm left a little lost as to my shade. I'm tempted to try NC20, or NW20 if I can score another sample.
On a related note, I tried to buy the Timecheck primer but they were sold out of that as well.