I ran a 2:25 at London yesterday. Want to add another anecdote praising the method and showing my appreciation to sirpoc and all the discussion in this thread (well, maybe not all the discussion).
Unlike a few of the other posters that have had success I am not someone who struggled to run high mileage. Genetically I seem to have lucked out in that respect and don't really get injured. Running for around 10 years now, slowly building up mileage and seeing the race times come down (did my first half in just under 2 hours).
Last year I ran a 2:28 at London, but was averaging 100 mile weeks in the months leading up to it and did a final block of 170+km weeks in the build up with some massive sessions. I was regularly running 13 hours a week, with my peak being 172km and 14 hours. I was absolutely destroyed during the build up and felt like I just about made it to the start line. Although I had a great race, it was the first time I didn't actually enjoy the training and thought if that's what it takes to get faster then I don't care enough. I discovered this thread shortly after and decided if this keeps me in good enough shape and healthy I'm happy with that.
Started in June of last year. Had a 3 week block of hardly any running in Autumn due to holidays and sickness but apart from that have just plugged away with the standard plan (4E + 3ST) averaging 8-8.5 hours a week. Easy runs are also super easy - I'm rarely breaking 5:00/km on easy days and am often a chunk slower than that.
Felt great throughout the standard training and then started the marathon block. Continued feeling good, with the only bit of noticeable fatigue being during the "special block" at the end. Weeks were pretty flat, but peak was 113km and 8 hours 40. It was basically the polar opposite to my previous build. On race day felt great and managed to pb by over 2 minutes, even with some slightly overly aggressive pacing.
Never dreading a sessions and avoiding constant fatigue has been such a game changer. I feel like I'm now a life-long sub-t convert. Even if/when I plateau, it keeps me in great shape and is highly enjoyable.