As I learned that The North Face Arnuva 50 Boa is the running shoe Dean Karnazes chose for his Endurance50 challenge (50 marathons in 50 states in 50 days) I got interested and decided to try them myself. Dean used five pairs for the 50 marathons, that's about 422 km/pair. I've tested them for about 400 km now and they feel as good as new. I hope to get at least another 400 out of them, but that remains to be seen.
Arnuva 50 is built for the ultra distance runner of both trails and roads. They are excellent on muddy trails or snowy paths but they are also perfectly ok for city streets. Although they are not as fast as a racing shoe they feel comfortable and reasonably light considering how stable and technical they are - my pair weighs about 730 g (size 10.5 US / 9.5 UK / 44.5 EU).
The most innovative part of the shoe is the Boa lacing system, which is both practical and addictive. Once you try the Boa, you will not want to use normal laces ever again. Boa offers quick adjustments using a dial on the back of the shoe, which is connected to a network of foot-hugging stainless steel cables. The new system enables you to adjust the fit of your shoes instantly if you can stop for a brief moment.
I'll probably buy another pair later on if I can find them - they don't seem to be too widely available.