We got some good luck with card distribution; the Epidemiologist needed only one card to complete one cure, the Researcher drew all five cards for a blue cure, and the Medic drew four yellow cards. We also benefited from our house rules; our change to the Epidemiologist made it easier for him to complete the last cure, and our house rule about choosing who goes first made it possible to suppress a possible chain reaction on the first turn, before we drew an Epidemic.
I also think that the Operations Expert is very strong; not only is that role extremely mobile, but it leaves mobility in its wake.
In this game, we got to a point in which we could have eradicated the red disease with one turn from the Medic, but we decided not to - and that turned out to be the right decision, because the red disease never required attention again. Usually, eradicating a disease seems terribly worthwhile if you can do it with a turn or two of work, but it seems that there are times when it's not actually worthwhile to do so.