Hi
My experience is only with live stuff and I have not used them on vocals or guitar amps.
I have had good luck with them on cello, violin, marimba, drum overheads, and for the "one mic" bluegrass thing.
They are cheap and tough.
I have had one go over on a stand as an overhead and it hit the deck hard.....no problem.
Some folks have stated that they are a bit dark but I think they are simply less hyped(flatter) in the high end than other cheap sdc's.
I have mixed one bluegrass trio a few times who supply their own KM184 and the Kel is much more manageable.
Again....all my experiences are with live stuff so things like self noise are not really an issue.
cheers
Roly

kel revival.

i bought a matched pair over the summer, and have had great results with them.

i tried out a few stereo-micing techniques and got a really impressive sound from:
the terrible pres of a ber. mixer
a tascam 4track (414mkii)

i've since progressed to using one hm-1 @ around the 12th fret, facing the soundhole on my acoustic, and another about 10-12" away from my head, with a make-shift pop filter for vox.

makes for some really great live two-track takes, and more recently i turned out a little demo by mixing down to my computer.

in all, i'm very satisfied with the mics, and for the price of a sm58, it's pretty hard to beat.

that said, i'm still not sure if i'm willing to make the leap to using a Brick or two for my phantom power, as the sound i've got now is really agreeable. the mics, on the other hand, i'd buy again in a minute.

*also, Kel Audio is a wonderful company to do business with.