Butt boards I have used them for years, my house, my daughters house, and customers houses. To date no callbacks, they totally do away with butt joints, are easy to use, and mud just like factory seams. Go to trim tex.com they make them and you can read up on them. I have 2 cases in my garage now. Go to drywall tips at the top of this page and Willy T tells about them from a few years ago. And as far as cracking why would they crack any more than the factory seam since you do them the same way.
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On the right is a picture of Myron Ferguson's book. In the book he describes how to do this and make your own.
The advantage is perfectly flat joints, which can be important if you have a counter or something dead straight that needs to fit flush on that wall. It's impossible to make a flat butt joint on a shared stud otherwise, unless you recess that stud or something.