大同小异
Much of a muchness.
There's not a pin to choose between them.

eg：John and Robert dressed much of a muchness.

中英俚语俗语来源：唐·卢同·玉川子诗集·与马异结交：“同不同，异自异，是谓大同而小异。”

同义词：不相上下 As well be hanged for a sheep as for a lamb.
反义词：判若云泥 A world of difference.