|Well, first off you need to compare the theoretical speeds. USB 3 & eSATA are close to the same but but can be hobbled by a slow hard drive.|
I would say that eSATA is fastest when transferring data from a SATA3 drive to a SATA3 drive.
As a practicality you need to consider the cost of getting eSATA or USB3 working and what other hardware you have.
See the articles links in the Google search below.
See the link below too. eSATA is covered there.