My husband got this for me for Christmas. I have already run in it several times, and it is a great top. The sleeves are long enough. The neck is not too high or too tight, so that it doesn't hinder breathing. I am 5'9" about 125 and the small fits perfectly, slim but not skin tight. I wear this with another long sleeve layer below and a jacket over the top for my cold weather runs, when the temp hovers between 20 and 30. I expect it will be great on its own with a tank underneath in fall or spring.