I also strongly, strongly recommend the short interval approach, unless you are a premier athlete. Last month, I ran my first full marathon at Disney. While leaving the Expo, I just happened to walk past a talk being given by Jeff Galloway. He was pitching 30s/30s or 30s/15s or whatever short interval is appropriate for you. He explained that your energy lasts longer, you are less susceptible to injury, and your time improves. Based on his talk, I changed my race plan--I could not quite go for 30s/30s at that point, because it seemed such a radical change from what I was used to--but I did drastically shorten my interval to 1m/1m. I saw quite a number of people following 30s/30s during the race. My only goal was to finish, since it was my first marathon. Here is the result--(1) I never tired the whole way, I promise; (2) my Fitbit heartbeat record of the race showed an average heart rate of 140 bpm, nice and low; (3) I got 6:14 time, decent for me (now 50-something) and included about 15 minutes standing time for my friend to use the restroom in Animal Kingdom; (4) I ran Mile 26 (because it was the last mile) without walking intervals; (5) my calf muscles were sore at the end, but I was back at the gym doing step aerobics on Tuesday; and (6) most importantly, I had absolutely the most fun I have ever had in a race,because I did not overstress my body.
So, I am a Galloway convert. Normally, I would have run the first 3 miles or so without stopping and then transitioned to 4m:1m for next Sunday's half marathon--I have done probably 6 Half Marathons that way in the last 3 years, normally finishing in around 2:30. I now plan to run 1:40m and walk 20s from the very start. (Maybe I will shorten the interval even more next race.) Discipline is the key--even though I could easily run several miles at the start without a stop, I believe Galloway when he says that the overall race performance would deteriorate and body stress and chance of injury would increase. You have to maintain the discipline not to run for uninterrupted long intervals at the start of the race.