I upgraded from a Black Cube to an Audiomat Phono 1. The soundstage is better, and it passes much more low-level information. It's on an entirely different level from the Black Cube, but also very different. It is very detailed (though musical), and not very kind to imperfect or over-affected recordings. It is a solid state unit, but has more of a "tube" sound than the Cube. I'd say that the Audiomat is technically "better" than the cube, but the cube sounds much more immediate and dynamic. I have also had a bit of experience with a stock COunterpoint SA3000 preamp, and the Audiomat has a somewhat similar sound. I'd say a bit more refined sounding (and a bigger soundstage), but a modified SA3000 might be better.
It really comes down to personal preference. The Black Cube is great, but I'd probably recommend the cube for rock, pop, dance music, or anyone looking for a dynamic phono stage (and it costs almost half as much as the Audiomat). Any classical/jazz listeners looking for a phono stage in the $1000 range should consider an Audiomat.