Is God perfect? There are people who do not believe that God is perfect because they see an imperfect world. They claim that a perfect God would not permit sin and death. They claim that a perfect God would not create creatures that were deformed.
CCC#1 God, infinitely perfect and blessed in himself, in a plan of sheer goodness freely created man to make him share in his own blessed life. For this reason, at every time and in every place, God draws close to man. He calls man to seek him, to know him, to love him with all his strength. He calls together all men, scattered and divided by sin, into the unity of his family, the Church. To accomplish this, when the fullness of time had come, God sent his Son as Redeemer and Savior. In his Son and through him, he invites men to become, in the Holy Spirit, his adopted children and thus heirs of his blessed life.
310 But why did God not create a world so perfect that no evil could exist in it? With infinite power God could always create something better. But with infinite wisdom and goodness God freely willed to create a world "in a state of journeying" towards its ultimate perfection. In God's plan this process of becoming involves the appearance of certain beings and the disappearance of others, the existence of the more perfect alongside the less perfect, both constructive and destructive forces of nature. With physical good there exists also physical evil as long as creation has not reached perfection.
In this part of the Summa, St. Thomas wrestles with the following questions.
Yes. By definition, God is all knowing, all powerful and eternal. Can't get anymore perfect than that, can we?
Is God perfect universally, as having in Himself the perfections of all things?
God is all good and all good things come from God. Therefore, yes.
Can creatures be said to be like God?
I would say, "only in a metaphorical sense." God is the way, the truth and the life. We are like God in the attributes that He has shared with us. Such as life. We are living beings sharing in the life which He has given to us.
Let's see how close those are to St. Thomas' answers.