QED 'Original' is similar (the same?) as QED '79 Strand' which for many years the gold standard speaker cable. 2.5mm^2, shotgun, no nonsense and a reasonable price. I believe that QED also now do a thinner 'Original' at 42 strands for a CSA of about 1.5mm^2.
I couldn't find the CSA of the micro, but to a certain extent the name gives it away. I recall it is 1.25mm^2.
In speaker cable, size matters. Given the same quality copper, you will always do better with a thicker cable. Whether this will be audible depends on you, the quality of your gear and the length of the cable runs. If you are starting from scratch, and space is not an issue, buy the thicker cable.