Arashi - you are missing the point though - different manufacturers make different coloured strings, and some make more than one colour - its not about the colour though, its about the feel and the tone
Tight strings you are referring to may well be Aquilas - they may feel tight, but on a cheaper uke most people agree they are about the best you can buy
Hilo black strings are slippy and bendy, but to my ear are pretty awful sounding. In the same way, Martin flouros are clear and bendy but sound great on the right instrument
There is therefore no right and wrong answer, but your decision shouldnt really be based on colour
WHat new uke are you buying - there may be other players on here that have the same uke and can share their opinions with you. There is no right and wrong, good or bad string though, depends on your ears and your uke