Constrictor is a screenshot utility for OS X. A positionable frame lets you grab the right area every time; then apply scaling and border effects, and save in a variety of formats or copy to the clipboard. It can tag its screenshots for easy Spotlight availability, and it can add thumbnail icons to them; it supports configurable hot keys, and it's even scriptable!
Obviously, the software developer has posted these positive comments themselves. I wouldn't buy anything from a dishonest person no matter how good his or her software product is.