The Covenant of Grace is Better
There are many ways to compare the Covenant of Works and the Covenant of Grace. If you need a refresher on the two, I would suggest reviewing chapter 7 of the Westminster Confession of Faith as well as Questions and Answers 30-36 of the Westminster Larger Catechism.
The Covenant of Works was made with Adam and the Covenant of Grace was made with Christ--but what are some differences? In the newly translated, Theoretical-Practical Theology: Redemption in Christ, Petrus Van Mastricht (1630-1706) sets out several pages of analysis and differences that are worth meditating on. In one such comparison, Van Mastricht offers this contemplative insight:
"The covenant of grace surpasses the covenant of works by a thousand miles..." (TPT, 4.30). Van Mastricht offers eight insights:
1. The covenant of works was from God as the generous Creator, the covenant of grace is from the same as the merciful Redeemer.
2. The former was from benevolence alone, the latter in addition from mercy.
3. The former was in the first Adam with a mere man, the latter in the second Adam with Christ the God-man.
4. The former demanded exact and perpetual obedience from man himself, the latter the righteousness and obedience of Christ the God-man.
5. The former was founded on a perfect nature without a mediator, the latter on the most perfect grace of Christ the mediator.
6. The former was mutable, the latter eternal.
7. The former produced a servant of God, the latter preeminently a son, heir, and joint heir with Christ.
8. The former concerned the exalting of the glory of divine wisdom, goodness, and righteousness, the latter in addition, the glory of mercy and longsuffering (TPT, 4.30).
Van Mastricht leads the reader through several meditative comparisons between the covenants and analyses the differences. The Word of God divides all of humanity along the lines of being in Adam or being in Christ. You ought to know some of these eternal contrasts, for as the Apostle Paul said, "For if by one man's offence death reigned by one; much more they which receive abundance of grace and of the gift of righteousness shall reign in life by one, Jesus Christ (Romans 5:17)."