There's more to the equation than the headwing/tailwind component, or even the slope of the runway. The obtacles or terrain that lies beyond the runway should be an important of the consideration, just as the type of aircraft involved. If you're talking about flat terrain around an airport with a slight gradient...then generally taking off into the wind is preferred. However, if it means an excessive taxi and the tailwind taking off the other way means a shorter taxi with less brake and wheel assembly heating, then the slight tailwind may be preferred.
If you're flying a heavily loaded supercub out of a canyon, downhill with the tailwind is preferred in nearly all cases; you go the way the water flows. It flows downhill, and so do you.
Suppose you have convective weather into which you'll be flying if you depart on the uphill, upwind runway? Going the other way may be your best bet...obstacles aren't always on the ground...it may be a cell, or another airport with high traffic density, or a departure procedure with a gradient that's unacceptable...again, many factors to consider.
Consider all the variables, and make your decision accordingly.