The beauty of the k&k is that it sounds extremely full bass wise. If you're gonna play gigs alone, that one could be for you. If you also get their preamp that cleans it up a lot and also allows for a nice sparkly high end, while still maintaining that low "bassiness."
The lyric is in one word, "amazing." I mean, it sounds like the guitar. You could practice unplugged all day and then go straight to the gig and change nothing in your approach/attack and you just get the guitar's own response. Having said that, to control feedback, it does have a sort of mid-centered tone and will definitely lack the low end of the k&k, so if you're a solo artist, it may not be the one for you. You could get their venue d.i., but there's only so much that can do. If you're playing with a band and can control feedback, you would love this pickup.
From what I know of the the anthem is that it has both an undersaddle piezo as well as a mic. The undersaddle brings the low end E, A and D strings, while the mic is focused on the higher G, B and E strings, so in a way you get the best of both worlds, though I'm pretty sure it doesn't bring the low end of the k&k, and I think that's why solo artists are more partial to the k&k.
The other thing to remember is that the k&k is passive (no batteries), and the preamp you can run phantom, so no batteries there, so some people prefer the k&k for that as well. The two lr baggs pickups require batteries for their onboard preamps.
Hope this helps. Lots of other forum members will know more than me, but maybe this is a good start.
