I've heard the dCS,and liked the results of it's upsampling,and later bought a Perpetual Technologies DAC and Upsampler/Interpolator.

Used together,the PTech units are amazingly good for the price,especially if used with upgraded power supplies rather than the wall-warts they come with.

I now use the upsampler set to 24bit/96kHz with a TAG Av32R DP,with again very good results....the sound via the TAG is smoother and more open than without the upsampler,and certainly less edgy than it can be otherwise.

I think the point of all of these systems is that like with everything else,they work for some people and some systems,and not for others,and particularly so where the upsampling,and/or interpolation of data to 24bit word lengths,isnt done very carefully.