If this thing was available six months ago I would have bought it instead!
However apparently 10 of the cores are the Cortex-X925 CPUs, which are a serious upgrade. Basically 10 performance cores and 10 efficiency cores that should be pretty competitive with any current apple CPU.
Seems close enough that it might well come down to if your application uses SVE (which the X925 has) or SME (which apple has). I believe generally SVE is much easier to use without using Apple proprietary libraries.
Of if you need significant memory bandwidth, apple M4 peaks at around 200GB/sec or so, the other 300GB/sec or so is available for the GPUs.
Seems quite plausible that 10 * x925 and 10 * A725 might well be more collective performance than apples 12 p-cores + 4 e-cores. But sure it's a bit early to tell and things like OS, kernel, compiler, thermal management, libraries, etc will impact actual real world performance.
Generally I'd expect the Nvidia Project Digit 10 p cores + 10 e cores + healthy memory system to be in the same ball park as the apple M4 max.