Hey Rich - choose the program based on your fitness level and race goals, as the 6 week beginner program is designed for beginning runners.
Good question and let me know if you have further questions - E
This is what I think. If you're running at the moment in a style that you're happy with, don't change. Why risk getting new types of injury as you make the adjustment? I signed up for an Eric plan because I had all kinds of chronic problems that were getting worse, not better with age (I'm 45), and I was seduced by the promise of pain free, injury free running. I'm a pretty experienced runner, but I went for the 6 week beginners and I'm glad I did. The distances and times are tiny, but learning an entirely new type of running means training entirely new muscles; like most people here, my calves were very sore for about 4 weeks. And for nearly 6 weeks I loved it. If you like structure and variety and the challenge of learning something new, and a real feeling of progression, it's a great plan. You do run a lot slower - the promise is that it gets faster with time. I haven't got there yet because after 5 and a half weeks, of following the plan to the second and to the letter, I got tendonitis in my left peroneal tendons and have been resting up. And if you look on the site, there's an awful lot of posts from people with injuries (sore knees, arches, feet, plantar fasciitis etc) which seems odd for a running style that promotes itself as injury/pain free. If this happens, you realise that with a virtual plan you're effectively on your own, so if it does go wrong, there's not much support, other than advice to let your heels drop. So think carefully about what you do now before you commit.
Hope this is helpful