Copolymer Line is made by mixing 2,3 or more kinds of materials
The main advantage is that Copolymer is thinner and stronger than normal mono line. Its also got less stretch.
Iv never used it but have heard good reports about it......ill stick with braid though
Monofilament means a single strand, the raw material is pushed through a die to produce a strand of line, so whether it's a single polymer or a blend of polymers, it is still monfilament. Braid is made by knitting several strands of monofilament. Almost all mono is copolymer now, utilising other polymers to replace the additives and plasticisers in the old nylon line making it more supple without compromising the strength.
Sunlight, ozone and exposure to oil and grease used to leech out the plasticiser in old nylon turning it brittle in a short period of time, a good copolymer line will resist attack for much much longer.