This is what your shoes look like after you ran 103 miles on them through the rocks, roots, and ruts of the Superior 100.
Prior to running Superior, these Asics Gel-Hyperspeed 4's had ~175 miles on them, almost all of that on pavement/sidewalk/asphalt/etc. Now, the bottoms are shredded and I lost a chunk of the heel pad on the right shoe. The white material - the part that is covered up and protected by the red weave on the forefoot and the black pad on the back - is much softer than its coverings and will likely begin to wear quickly. I'm not sure how much longer these soles will last.
The Superior 100 stressed my shoes more than any other race I've participated in, even the 50K I ran on the Superior Hiking Trail earlier this year. The rugged course chewed up my flats. Now they look like they have 500+ miles on them and are ready to be retired.
Even with the damage to the shoes, I stand by my footwear choice. The lightness of flats is invaluable over such a long distance where even a minimal decrease in shoe weight can (should) reap benefits when compared with something bulkier and heavier. There are also the additional benefits of a lighter, more efficient and economical stride and the lack of running-related injuries which were not caused by acute trauma.
Who is to say whether my feet would have taken the pounding they did had I run in other shoes? My guess is that the level of discomfort I faced would have been the same. I lost my toenail on my right big toe post-Superior (again) as a result of slamming it into various roots and rocks on the course, and I did the same thing back in 2009 when I ran the Superior Trail Races Spring 50K for the first time. And that race I wore bulky trainers, also from Asics. Those shoes were bulkier in the soles and had similar protections on the front. Despite the potential additional protections of the bulkier shoe, the trauma I experienced in both races - at least toenail related - was the exact same.
When other runners learned I was planning on running this race in flats (or sandals, and thankfully I jettisoned that idea), several informed me that the race caused their feet - and toes especially - felt like they had been struck repeatedly by a ball peen hammer. I never experienced this feeling. The soles of my feet were tender from blisters and the general pounding (they eventually numbed around mile 65 or so), but outside of the trauma from the to-be-lost toenail, my toes stayed relatively happy in my flats. The tenderness was similar to the feeling I had when I hiked the trail in 2008; at that time, I wore Salomon trail shoes, and my feet at the end of the day felt like someone had tapped my soles with the pointy side of a meat tenderizer for the past 12 hours. Again, who is to say that I would have felt better in a bulky road shoe or even a so-called "trail shoe?"
I ran in what was comfortable to me, and I have experience on the trails with this type of shoe. No shoe is going to allow you to slam into rocks or roots and come out unscathed. Similarly, over a long enough timeline one's feet are going to hurt. Some runners swear by the marshmallow shoes that are Hokas, but I have already established that such cushion does not work for me.
In sum, my flats where the best choice for me, and I can't imagine the stress the race put on my feet would have been any less had I chose different shoes.