When I run inside on the treadmill or in hot weather, I tend to sweat quite a bit. This t-shirt will get wet, but despite that haven't had any chafing issue. While they will get wet (and I still have to find one that doesn't), they will dry very quickly, which is big plus. They are very comfortable and all in all, I really like them (I have now 3 different colors of these t-shirts).
I loved this shirt so much that I bought two additional, as I run frequently with training for half-marathons and marathons. It's so comfortable one hardly knows one is wearing it, and it does an excellent job of wicking away sweat. I tend to sweat profusely, and this shirt doesn't cling to the body like many shirts meant for exercise. It's literally the only shirt I wear while running.
This is an incredibly light weight and very comfortable running shirt. That being said, by the end of most of my runs, the shirt is SOAKED. It seems like it sponges up sweat rather that wicks it away. Even soaked, its very comfortable, but it is an odd detail.
This is a decent top, but it doesn't wick sweat as well as other Brooks' tops. I am a very heavy sweater and Brooks' tops are usually better than other brands at not getting completely soaked. However, this top isn't as good as prior versions. I really don't understand why I have tops from a few years ago that are much more effective than current models. A lightweight, comfortable top is not hard to find, but one that can handle heavy sweat is quite difficult. I returned it and will try something else.