I agree with poster great Scott. I think, as far as marathon anyway, their program is great. Look at what they did this last summer/fall. Steph gave a summary in a SM post of the last several long runs. She was doing them side-by-side with Kellyn with very few exceptions. I was actually following this through their site while it was happening, but seeing her list the workouts at once like that made it clear that the bases were covered.
I don't remember the order or the exact details, but if was something like:
10 moderate, 10 MP
A long one (24?) alternating MP and a little slower
26 with 18-24 at MP
Moderate 30 miler
16 at MP
Very marathon specific. I think I'm leaving a good one similar to these out actually, given that I didn't look it up just now, but that is the kind of thing they do. These real hard ones are as much as 2 weeks apart. I suspect most objectors would have them do more 10k-specific stuff, which is to say many folks believe one should train for a 10k (or even 5k, which both Pfitz's book and Shorter in his prime advocate) but add slow long runs. They do actually do some shorter intervals and alactic leg speed work too. They're just not the focal point and are just moderate days.
At any rate, I believe it works. Both Scotts at TMP, the ladies at NYC. These performances could be beaten by the best of the East Africans, and Rupp or Seidel if they have a good day, but few other Americans. Maybe you'd call them 2nd tier (US) or 3rd (world) but that is saying a lot. Take a random top-10 NCAA XC finisher, for example, and you'd do well to get them to their level.