OVH wins in everything. And I will say why!
OVH wins against Contabo in everything since OVH have a great network around Europe. Also they have Anti-DDoS for Game and many locations around Europe.
Their Anti-DDoS of OVH is more strong than Contabo, the only way to take down OVH servers is with another OVH server. Otherwise is not easy.
It needs to be a powerful attack to take down OVH.
In resume: OVH wins over Contabo in overall. OVH great Anti-DDoS Protection, good prices, network and good servers.
Contabo might be good for Ping, cheap and a good alternative. But since Anti-DDoS is important, OVH is on top.
EDIT: I See that Contabo uses DDoS Protection from Colt, I don't know if they are better than OVH. But I will stand with OVH.