So overall, is the only disadvantage to using a pool such as Slush's vs. a PPS pool the fact that your payout is not always consistent day to day?
It's more to it than that. The payout varies not only from day-to-day but also throughout the day. What this means is that if you are not mining 24/7 x 30 days a month where this variability washes out, you may rejoin the pool after gaming (etc.) and run into a 7-10 hour batch and get 1/2 or 1/3rd the reward you'd get at a PPS pool. Suddenly your GPU just mined inefficiently for 7-10 hours! At a PPS pool, it would get a consistent reward, which means you can leave and re-enter a PPS pool any time (a lot more flexible).
Also, because of the day-to-day variability, you have a situation such as right now when the 7-day pool luck at Slush's has fallen to just 87%. So if someone joined Slush's pool 7 days ago, they would have made less money than any other PPS pool. Slush's pool ultimately has to come back to a monthly average of roughly 100%, which means situations where pool luck is low have to be compensated by areas where pool luck will be high. Due to this variability I think it makes a lot more sense to hop to Slush's pool when the pool luck is very low (40-50%) and ride it back up to 120-150% and then leave again to a PPS pool because you know for sure it'll drop way lower to get to that 100% monthly average.
Slush's pool also charges a 2% fee, despite not being a PPS pool, so really that's a lot of risk to put up with its variability and definitely not worth it for anyone who isn't mining non-stop 24/7.
I just joined Mt.Red. Do I need to set up 2 workers or can I just have both cards log in as the same worker? I was logging in as the same worker with both cards for Slush's pool.
Also, what is the APIKEY? It is blank right now on my Mt.Red profile page.
I have no idea what the API Key is. Mine is blank. I was under the impression that you needed to set up a separate worker for each of your GPUs/miners. Interesting how you were able to mine with both under 1 worker.