All a compression does is choose what will compress to less than the input size, and what will compress to greater or the same input size. Pigeon hole principle.. Whatever gains are supposedly had over zlib mean that these other compressions are assigning meaning to other aspects that might not deserve to be pigeon holed to smaller input sizes.<p>Theres no magic in compression, if I make unintelligable garbage artifacts compress, I lose that domain for compressing intelligible repeats or other reasonable patterns.<p>A good compression always values patterns OF intelligible deliberate meaning -- theres no holy grail. Zlib is very competent at this.