It seems I on yac.dontmine.me my hashrate would fluctuate between normal hashrate and having lower hashrate with about 2 MH/s.
So the payouts were slow, etc.
Also the fee was huge. 2% and also withdrawal fees.
The servers would sometimes block miners I heard.
On
http://yac.coinmine.pl/ I'm getting a constant full hashrate, it's what it's supposed to be, no lag, and best of all: 0% fee ^_^
Try it out, we need a little more hashrate, we have 91 MH/s but could with around 150-200 MH/s.