Even if we focus on 120k writes and ignore the low transaction number then it's still an average result. They use c3.4xlarge to run 5 shards each with 3 replication factor. It's 1500 writes per core (120k / (5*16)). Etcd easily does 5227 writes (I believe it can do even more) on "Standard DS12 v2" so it's 1306 per core which is very similar.