Not really an "advantage"; however, the fact that it's written by the same guys that wrote cgminer (and BMminer being a bastardized version of it) , would suggest that the connection code from proxy to miner would have to be as good as it gets in ckproxy. That's not to say that one is "better" than the other, just that that ckproxy/ckpool can't be "bad" at handling the connections.