So, how does one find out which are the top (15) (25) MAC stores? It's always possible that there is one near me, or one that i will point be near at some, here in California.
As others have said, i prefer to swatch.
I've had some bad luck with lipsticks i bought when i trusted the descriptions and on-line photos, when the color didn't look like its picture - or looked very different on someone with different coloring than mine.
Also, in the past (i'm especially thinking of the 1970s) lipsticks often changed color while being worn - and this was NOT a feature. There i'd be, excited to get an unusual color, and after 15 min or 1/2 hour it would have become muddy orange-y. Lipsticks haven't changed on me often in the past 15 years or so, but from time to time they still do. For example, Asian Flower, a Sheen Supreme Lipstick, starts out a nice, slightly pinkish lavender - i love the color in the tube - and then it turns soft fuchsia on me after a few minutes and i only rarely intentionally wear fuchsia. I can wear a lavender or violet lip anytime. But i really have to do a whole face to wear fuchsia.
Testing lipsticks is a good thing. One can return mail-ordered MAC, but one has to pay for the postage and insurance, so returns are costly.