When I first ran bft, I landed on midfoot. Nowadays, some years later, I tend more to land on the ball of the foot. I haven't had problems neither with the one nor with the other. Curiously, after many months running in minimalist footwear , but walking in normal shoes-and with orthotics for a very pronounced arch-, the summer came and I only wore the same kind of shoes for both, running and walking: aquashoes (just 4 mm of rubber between the floor and the soles of my feet) I walked bft a lot too. I developed some mild Achilles tendonitis, from which I am recovering now.
I think walking was the activity to blame. It is easier to run than to walk on your forefoot, at least for me. The more my heels touch the ground, the worse. Running and walking are slightly different skills. Maybe you can have one without the other. Mine is not the only case I've heard about.
These days I don´t go running and I'm feeling better. I wear my orthotics and normal shoes in the street and at work, and I'm bft at home. As always, I work out barefoot, too and I will begin to run in minimalist footwear soon.
And I have found a splendid way of keeping myself fit for barefoot work, without running: barefoot sled dragging. In sled dragging, to land on the forefoot is actually easier than to land on the heel. Furthermore, the knees are always bent-as they should in bft running. I combine bft sled dragging with kettlebells, etc