Shows sweat in a major way.
I sweat more than average; one reason I shop here is because I figure the clothes have a better chance of dealing well with that. But I bet even the average person will be disappointed with this shirt, especially because it's otherwise a great tank. Soft, form fitting, cute like the picture suggests. Even large busted women would be able to wear it without a bra. Just don't have boob sweat.
If you don't sweat at all during the course of a normal day, go for it.