A year or two ago after reading both Mel and Chad Waterbury espouse the benefits of the ab wheel, I bought one and roll outs quickly became one of my favorite exercises.
Yesterday, for the first time since my surgery, I was able to put enough pressure on my chest to do these once again and the good soreness that I'm feeling today reminds just how great this exercise is.
For those who have never tried them, I highly recommend them. Another great thing about them is that there is a long line of progressions so that a rank beginner to an elite athlete can incorporate them in their programs.
Here is an excellent article by Mike Boyle on the rollout:
This video, while focusing on the standing ab wheel, shows how to use the wall to help with the beginning progressions. This part can be utilized with the swiss ball roll out and the kneeling versions as well to start.