I will praise the name of God with a song;
I will magnify him with thanksgiving.
This will please the LORD more than an ox
or a bull with horns and hoofs.
David knew that the Lord was most satisfied with us when we were fully satisfied in Him. And that sort of heart's satisfaction pours out in real, uncompromising praise. David would let his soul praise the Lord without any inhibition. This would please God more than any sacrifice. David does not think he should replace sacrifice with praise, but rather that his heart given over to praise and thanksgiving along with his sacrifice would be much more pleasing than a sacrifice by itself. God would be satisfied with the required sacrifice. He would delight in the sincere worship that accompanied the gift at the altar.
Really there is a balance of obedience in the context of spontaneous, relational worship. God wants us to know Him in both ways. We don't pit them against one another. Worship cannot be real worship if we deny God's command. And rote obedience without worship is dry ritual that focuses on self-saving action. Dynamic faith is a mix of obedience and relational worship. It is both volitional (an act of my choice by my will) and emotional (an engagement at the heart level). It requires both commitments and it delights in the joy found in God.