Currently using 3.5mm Jack to Jack Line2 to connect my BT3 Speakers to my TV while watching Netflix is the one supplied with the Speakers. Would a branded product offer any improvement?
With analogue cables, it is possible to get improvements, but it going to be marginal and you will need a really good set of golden ears to hear the difference!
HDMI is the big con. If the cable works well enough that you get a clear picture with no sparkles or drop out, then a better cable won't improve it.