How would you briefly discuss the strengths and weaknesses of the Articles of Confederation and the Constitution?

First of all, let's look at the strengths of the Articles of Confederation:
This system of government helped the American colonists defeat the British in the Revolutionary War. The Treaty of Paris that ended the War was also negotiated under the Articles of Confederation.
Because they formed such a loose, decentralized system, the Articles of Confederation were more in keeping with the principles of radical republicanism. As ultimate sovereignty resided with the states, this made it more difficult to re-establish what the colonists regarded as the tyranny of British rule.
Now, the weaknesses:
After the War, the United States needed to speak with one voice on the international stage. But without a strong, centralized government, it was simply impossible, making it especially difficult to resolve territorial disputes with other nations.
As ultimate sovereignty resided with the states, Congress had to rely on state authorities to deal with serious domestic disturbances. If they didn't or couldn't, there was very little that Congress could do about it.
The United States needed to pay off its crippling war debts. But without a central bank, it was unable to do so.
The weaknesses of the Constitution:
It placed too much power in the hands of a strong, centralized government. This was regarded by many as a betrayal of the Declaration of Independence's republican spirit.
It infringed states' rights. The Revolution had been fought over the liberty of the states to determine their own affairs. By taking away that liberty, the Constitution, it was argued, had simply replaced one form of tyranny with another.
The strengths of the Constitution:
With a strong federal government at long last, the United States could be a major player in international affairs, speaking with one voice instead of thirteen separate ones.
Now able to pay its debts, the United States could be taken seriously as an economic partner. This led to increased trade and commerce, greatly improving the state of the country's shattered post-war economy.
The federal government could now be used to suppress potentially dangerous outbreaks of political disorder and rebellion, wherever they took place. This was a much more effective method of dealing with domestic disturbances than relying on the individual states.