What I find interesting is the number of people saying the marathon is harder, even though I also suggested in general terms equivalent VDOT's doesn't mean they're equally hard. In other words, if a 60min 10 mile is a 58 VDOT and a 3hr marathon is a 53, I would have put the "hardness" equivalent somewhere in between, say 58 and 56 respectively.
If we had the data, we could probably find the average gap in VDOT's for people finishing races around those times that have raced both distances (a half marathon would be more feasible). It would probably be fairly accurate given that the VAST majority of people are racing all out at that level. But if anyone has a statistical conjecture on what the actual gap would be, I'd be interested to see it.