I think all major CDNs use some form of anycasting as it's pretty essential that you own your IP space. DNS-based load balancing can also be finicky as you'll h

I think all major CDNs use some form of anycasting as it's pretty essential that you own your IP space. DNS-based load balancing can also be finicky as you'll have to deal with recursive resolvers, so a combination of anycasting and DNS-based load balancing probably works best.