The series 4 that I had used for five years suddenly stopped turning on, and after considering new and used models, I thought that a used model would be fine for my current usage situation. However, I thought I might be concerned about battery degradation if it was a used Series 4, so I decided on a Series 6.
It was a C grade, but only one spot scratch on the side of the crown that I thought was this? I have only one spot scratch on the side of the crown and it doesn't bother me at all. I don't know how to compare it, but it's as good as flawless compared to the 4 I've used up. The battery status is 85%, and I'm happy with that too. I put it on the charger every day anyway.
Overall, I am very satisfied with my purchase.