Fishing lines. Do you get what you pay for?

I recently landed a 20lb Carp on a pole and a fine line (yes I'm still mentioning it). The line was Guru N-GAUGE in 0.13 thickness. My recent quest is to find a decent fine sinking line for float fishing in around a 4lb breaking strain. I came across some Maver Jurassic that on paper seemed to fit the bill. It was finer at 0.16mm and had a higher breaking strain of 5lb 14oz than the line I was using at the time the Guru Pulse 0.18mm and 4lb. The advertising stated the Jurassic had a high knot strength etc, etc, but It didn't even come close and is totally unuseable. This is why I made this video, not to knock Maver as they make some great gear and this could just be a bad batch, but to ask the questions. Is it worth paying a bit extra for line and do you get what you pay for?
Carp Fishing