The answer is both. One should strive to keep the commandments out of love of God. But if one is unable to do so (for whatever reason) keeping them out of fear of God is just as acceptable.
Zev Steinhardt
Thank you, zev.
I have no more questions left. 
WRS
Somehow, I doubt that. In any event, I hope not. When one stops asking questions, it means that he has stopped learning. You seem far too intelligent a fellow to allow that to happen.
Zev Steinhardt
Okay, so I lied.
Yiras shamayim, fear of Heaven - what is this fear like? Is it fear as in, “I’m scared Hashem will do something to me!” Or is it fear as in, “Oh, Hashem is so much bigger and more powerful than I am. I ought to heed His commands” (that is, more akin with awe). Which type of fear does Hashem want His people to have, that the prophets try to bring out through their pronouncements?
WRS
The three “intentions” of Catholicism were, I believe, derived from rabbinic thought:
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Based in love – I will not succumb to temptation because I love God and will do what He commands.
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Moral – I will not sin because I know sin to be wrong.
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Prudential – I will not sin because I know the consequences of sinning.
The first is considered “perfect”; the second two, “imperfect, but acceptable” intentions.
Zev or another expert on Judaism should speak to how these are seen in Jewish thought.