I've had good luck with Blue Jeans cable Cat 6 cables and LINKUPCat8 Ethernet Patch Cable Double Shielded cables. One thing I think speaks to both of their quality is the fact a Fluke Instruments cable test is included with each cable which certifies their performance. How many boutique audio cable makers include test documentation with their products?
Audio Grade Ethernet Cable
I've been thinking about getting a DH Labs ethernet cable. My thought is to get my crappy router as close to my Bryston BDP 3 as possible, so that the cable is only 0.5 meters. I do have a TeraDak LPS connected to the router. Is this a waste of time and money? I know the cable is just a couple hundred dollars but I don't want to spend that much just to realize again that my local files will always be preferable.