I just completed a 15 hour AR on high intensity training. I started CFE about a month prior to the race however my previous routine was similar training. With that being said I am now using CFE for a few reasons. The first is I have always been a train hard type of person. Never into jogging but instead going all out until I couldn't. However, I was always an over trainer. I was the guy who would go all out for three weeks and then die. Next thing I know is I have t take a week off then do it all over again. Don't get me wrong I got great results but always knew there had to be a smarter way. Just never though about the whole you get faster by recovery over more training.
Second, I have the ability to be tested within a human performance program. This is everything from flexibility, power, anaerobic power/average, and VO2 max as well as lactic thresh holds with HR's. My goal is to to 3 months of CFE programming and see the results.
To get more to your question... yes I had good results at the last race I did. It was only 15 hours of racing but it was still 15 hours of racing. I felt good the whole race for the most part (weather was 30's and raining the whole day) had no soreness the next day. I did have a little overuse in a few joints but due to weather I think that was a lot. I also didn't consume enough calories for the weather which took its toll and caused cramping. With all of that I truly felt like the training was working. I pushed hard and went faster than I thought (we ran a 9minute pace on foot the whole time which is faster than normal for us) and my legs were exhausted by the end but every transition I felt pretty good after 5 minutes of sitting and getting ready.
Overall, I have become fond of this training and I started a blog a short while ago to track my results, gear, training, etc...
The big test for me is going to be a 50 hour ar in about 8 weeks. This should truly prove how it all works. Especially since two of my teammates have the ability to compete on a pro level.
Here is my blog feel free to comment, give advice etc.
http://aaron-artraining.blogspot.com/I also agree that nutrition is key to racing as well as a plan and following both of them. Hammer puts out a good manual on this on their site. It's more geared to using hammer supplements but they give a lot of good info on calorie consumption as well. This might be my only issue with CFE for beginners. You need to train how you fight so to speak. If you are CFE'ing for an ultra you need to know and understand your body when it comes to calories. For veterans this isn't usually a big deal. If you have never run a distance where you need to consume calories then you need to incorporate this into your training. Even if this means doing it on the TT days. Learn what works and what doesn't. Do pro triathletes train transitions? Of course they do, and they train eating while racing as well as every other aspect of racing.
I follow CFE with one alibi. I do training session with my team which of course last more than a short time. I do these and train nutrition at the same time. I know it isn't CFE theory but still have to build the team at the same time.
This is all my opinion and if you feel different let me know!