Out of the aftermarket axles I'd recommend either the RPM Dominator Or Lonestar Axcalibar. All axles will bend or break if beaten on hard enough. The beauty of the Lonestar is they will fix it or replace it for free. They definitely stand behind their product
When I was talking with Mike at HRE as we were working on my bikes we discussed axles. Mike use to be the mechanic for Izzy Burgard when they were racing nationals. According to Mike and his experiences, he preferred the Lonestar axle because they tended to bend rather than break so at least you could finish the race. He said that Durablue had a tendency to break so they avoided them, and RPM was somewhere in the middle. But they stayed with lonestar because of the support and how if they bent an axle during the races they would literally walk over to K&K who was a Lonestar retailer and swap the axles out for straight ones right on the spot for free.