Monster makes some Bomb RCA's from what i've experienced and heard. I have about 160 feet of the knu 0 Gauge (kca) in my car and I love it for the price, but compared to my Monster 400 series (ofc) 0 gauge, I would choose the monster wire all day. They both have oversized wire, the outer casing on the Knu just did not impress me compared to the monster, but the Knu is more flexible for sure.
Never worked with the Knu RCA's though, I have been running Kicker Z2 RCA's for a couple years now and have had zero issues.
Just my .02