I am looking for organizations that have used SkillPath to provide leadership development to their managers. I have never worked with them and would like some feedback on how they manage the client relationship, the actual value of the content and the exercises performed during the course, as well as the experience of their trainers. Any feedback would be helpful.

I have not been very impressed with Skillpath in the past. Their public seminars seemed to be more fluff than substance. Against my better judgement, I let my manager talk me into attending their audio seminar on Supervising Remote Employees recently. It was pretty bad. I ended up writing my own seminar on the topic for our new managers, so the money I spent on the Skillpath seminar was wasted.

I would tend to agree. My best experiences have not come from the larger off-the-shelf training type companies. While they claim they will customize their work , they don't do a great job.
I typically use smaller consultancies who are willing to listen to my requirements and build training for me. Possibly slightly more costly at the outset, but if you are planing this for the long term, well worth the investment.