A question that rings throughout the entire work of Machiavelli's The Prince; this ever existent thought has readers questioning the morals of rulng parties in both the past, and present.
To indulge deeper into this question, we must break down the very fabric of human nature. First of all, are we more likely to follow someone that we fear, or love? I myself, would not doubt that fear would cause me to become a victim of extortion. Someone that I love, could not force me to be at their will. So, it all comes down to whether your goal is to be oppresive, or sympathetic. To rule with an iron fist, or be pushed around, as though you are a spinless insect.
So all in all, if we are to be totally honest, fear is the more politically stable choice, while love can bring you down in the end.
In addition, it is easier for one to be loved, and then soon make a wrong move, and end up on the bad side of one, or many. But fear is not so easily resolved. It's like trying to convince a child that there isn't a monster in their closet. They may say that they believe you, but when night time comes, they'll still be checking before they turn out the lights.
Fear will always be present in our society, it's inevitable. But love can be dissolved, and forgotten. So if a conclusion has to be made, on whether it is better to be feared, or loved, the sensible choice is feared. It's a stable situation, no matter how much you are loathed as a human being. In order to maintain your strength, you must first strike fear into the hearts of those around you.
Of course, this is only my opinion. Feel free to question it, as you will.