I think this is a very important issue and you shouldn't just choose one because you can't be bothered testing them, you have to ALWAYS choose the right size shape and colour to get the most performance out of your laces, and don't buy them from just any shop, research the brand on the internet ask peoples opinions on their comfort (this is VERY EXTRA important) once you have all this you have to pick the right colour, there is NOTHING worste in life then to have shoe laces that don't look perfect, also make sure to clean and then treat your laces very well to keep them looking perfect and ofcourse so that the performance hasn't decreesed, with this i leave you, and remember choose wisely and dont be afraid to travel far and dont hold back with money either!