I am new to mining cryptocurriences but thought I would input my two cents and you can take it's worth just as that.

I mine at zeus and pooltobe's pool, I am only running a 460 gtx at around 100 gh/s and notice a small difference between the two. maybe this is because of the fee's I do not know.

But I could imagine what a small difference is at this low end of the scale, could become a very noticeable difference at a higher end of the scale.

I am currently on pooltobe's pool just to spread hash, it's not much but I figure spreading hash is the most important thing to help keep a coins health well.