Sacramento is a tough market to be an AA flyer in. Their only flights go to DFW or LAX so you're going to spend extra time in the air to go east. Even with the US flights to PHX and CLT, you still have to go out of the way. The upside is 100% flight miles plus 100% bonus miles if you fly at least 50K.

If you're buying paid first class fares, though, you may end up better with the new revenue based programs at UA and DL. At the 50K level at UA, you would bring in 8 miles per dollar spent, less taxes. Both UA and DL have the eastbound flights that would work best for you from SMF. You pretty much need to look at what you spend for your tickets and then decide where the best return in miles is.