It's so hard to recommend shoes since everyone has such different feet. I was using Salomon trail runners, went through at least 6 pairs before realizing they were too heavy to run over 50K in so I now run ultras in regular Brooks Adrenaline. The one thing I found while working in the footwear department of REI and getting extensive training in shoe fit was the importance of after market insoles. Although they do help with cushioning, they are more for biomechanical purposes. Check out Superfeet