I have my miner split 50/50 between Hashcows and Middlecoin and after 5 days Hashcows has actually been outperforming Middlecoin. In fact Hashcows has paid out 29% more than Middlecoin. Of course, YMMV. It seems like when one pool does good the other does poorly. IMHO splitting between the pools evens things out and makes earnings more stable than just mining at one or the other pool. As far as I know, the only balance you can currently trust at Hashcows is the final payout at 10 PM Central Time.
My hashcows balance says: Confirmed exchanged 0.00177260 and balance 0.00984785.
With middlecoin i make 0.012 btc a day. Hashcows needs to get to at least 0.0361 by this time tomorrow to beat middlecoin. Tho I won't hold my breath.
Rejects for hashcows is approx 3.6%.
Since dogehouse has more hash than multipool with multipool spending the majority of its time mining doge, I might trial there. Dogehouse needs to beat the 0.012 btc/day (7000 DOGE approx) that I do on middlecoin which has set the benchmark.