i've owned and extensively used both the km184s and gefell m300s. they are actually quite similar in sound, with the gefells having a bit more low-mid response. both are a tad bright for my taste, but are both pretty good all-around mics. i tended to have to use each of them slightly off-axis to round off the top end some when close-micing in the studio, and both are rather thin for diffuse field applications (distant micing). both mics are designed for near field use, but can be effective in the diffuse field with careful bottom end EQ added, or some judicious low-mid band compression. if i were pressed, i would probably give a very slight nod to the gefells - both have excellent build quality and generally professional sound. the gefells are a bit more affordable, the neumanns have a bit more cachet...