계구우후: 계구 우후 [鷄口牛後] Better be the head of an ass[a dog] than the tail of a horse[a lion].; It's better to be a big fish in a little pond than a little fish in a big pond.
우후죽순: 우후 죽순 [雨後竹筍] 새 집들이 ~처럼 들어섰다 New houses sprang up like so many mushrooms[weeds] after a rain. 유사품들이 ~처럼 나타났다 Copycat products appeared[cropped up] like so many mushrooms[ like crazy].