After using one of Ben's marathon plans to great success, I decided to give the ultra plan a try. I actually used it for a 100 miler and could not be happier. The plan is easy to follow but has lots of detail and sophistication — so much more than just "run X miles this week with a long run of Y miles." In particular, the regular speed work keeps things interesting and really improves running economy, so even for an ultra it's really important. If your ultra is hilly you'll need to track your weekly elevation goals on your own, as that's not in the plan. But the plan worked perfectly for me: I finished 24 minutes faster than my target. Cannot recommend more highly!
I love running so don't need the motivation or accountability of a coach to run, I sometimes need the opposite and be told not to run - following a running plan makes this easy for me as I look at what is required and get on with it. For the price and amount of training this is a bargin - very happy :-)