antminepool seems perfect so far. I'm getting within 5% of the calculator, even after 11/127 orphan blocks for the last 24h.
nlpool has 12/37 (32%) orphans for the last 24h. I don't know what's wrong with that pool, but it is not normal.
maybe the lots of disconnections and high latency causes orphan blocks on nlpool
edit:
i also observed, instability in blake2s or any dual algo's connection, affects eth efficiency. i hope claymore would look into that as well.