seriously, with the karma you can do everything that you can on any other machine, the only problem you will have is sampling new sounds and putting it to the karma because you cant sample on it, however, the karma has so many programming features you can actually take existing sounds and make the better or to your own taste.
if i where you i would keep the karma, and look into an exteranl sampler that you could control via midi. i.e. sample on the sampler, then control those samples from the karma, or the ultimate combination would be an mpc2000xl and the karma. definately keep the karma if you got the $$$$ for an mpc, no better combination except maybe the mpc and the triton, but the karma and triton are the same except the karma has karma and the triton has a sampler.