My experience was similar to surprised's from June of 2007. I'm a somewhat embittered former doctoral level Capella learner who earned a 3.76 GPA through my masters with another institution, a 3.933 GPA all through the doctoral coursework with Capella, and who had no problem passing the comps at Capella the first time around.
What was my experience during the dissertation process? A lack of oversight from my mentor resulting in many mis-steps and dead ends, months of delays in the development of my proposal because of the same, and a continuously-frustrating lack of "connect" between the guidelines that Capella's School of Human Services provided at the time, and what my committee was even aware of-in the end I withdrew out of frustration.
I will likely always regret withdrawing, and I know I'll regret not earning my doctorate. I honestly, though, saw no end to the frustration. After it all, and as an educator in a public school district (K-12), I have a very hard time understanding how anyone could be willing to accept anything less than excellence from an institution that charges $50,000+ for an educational program.
If anyone has had a similar experience, please send me an e-mail at searchinglearner@juno.com, I'd be interested in comparing notes.