"This is the confidence we have in approaching God: that if we ask anything according to his will, he hears us. And if we know that he hears us - whatever we ask - we know that we have what we asked of him" (1 John 5:14-15)
"Do not be anxious about anything, but in everything, by prayer and petition, with thanksgiving, present your requests to God. And the peace of God, which transcends all understanding, will guard your hearts and your minds in Christ Jesus" (Philippians 4:6-7).
"And I will do whatever you ask in my name, so that the Son may bring glory to the Father. You may ask me for anything in my name, and I will do it" (John 14:13-14).
"When you ask, you do not receive, because you ask with wrong motives, that you may spend what you get on your pleasures" (James 4:3).
No kind of prayer is more powerful than one that is from the heart. It does not matter whether it is made by your own words or by the Rosary because God looks at the heart and He already knows your needs even before you ask of them. If it is from the heart, God will listen to you.
As for me, i prefer to use my own words because
".. the mouth speaks about what overflows from the heart." (Mat 12:34)
"If you declare with your mouth that Jesus is Lord, and believe in your heart that God raised him from the dead, you will be saved" (Romans 10:9)
Merry Christmas..