I love my 6600P. I did not test drive the 6500. A friend told me to get a xxxx. I thought she said 6600. LOLs she said 6500 cause that is what she has and she had not experienced the 6600. When she saw my machine in action and then tried it she agreed it was a sweet machine. The accufeed is wonderful! I am sew happy with my 6600P and would suggest it to any quilter.