Cat5e may be theoretically better, but CW1308 is physically less obtrusive. What is most important to you?
I had a similar situation, where I needed to site the modem approx 20m from the master socket, on the opposite side of the house and on a different floor. I used Cat6 cable, mainly because the wiring was entirely hidden, but also because it had to run fairly close to mains and solar PV cables, and I wanted to reduce signal degradation as much as I could.
It has run without a problem ever since.