As you're probably aware the server that you use has little impact when the DDoS sends enough traffic to actually saturate your allocated bandwidth. Anycast provides a good way to handle DDoS, along with proactive monitoring and defense mechanisms, but at the end of the day DDoS are still extremely difficult to defend from completely. The downside is that Anycast is expensive and thus you need the capital to build it out and run it - which often raises the cost of systems built using it.