The alternative to Cmd + Shift + 4, but with more options
Personally, keyboard shortcuts me enough when taking screenshots or a specific area of the desktop. And if you do not like PFD format, you can always set the tool to be made catches default to another format like JPEG, among others.
But sometimes it is missing a timer, leaving us time to move through menus of an application before making a catch, for example. For this and other specific cases is SnapNDrag.
With SnapNDrag you can make a catch in the desired push of a button format, and then drag the capture from SnapNDrag any other application, such as an email client if you want to send a friend, your photo editor or any other program.