Depends on what you use it for.
The CPU of Ryzen is better than that of DGX Spark, especially for modern programs that have been updated to use AVX-512 (i.e. it has a significantly higher multithreaded performance).
Only for GPU applications the NVIDIA system is likely to be better.
For inference, the prefill on the DGX Spark is like 5x the speed. Decode about the same (both bandwidth limited to about the same memory speed, unfortunately).
Difference is on the Spark you can use and learn CUDA, vLLM, SGlang etc which is the industry standard.
I bought mine (ASUS version) back in December with the intent to learn that stack of stuff. I've been on and off with it but it seems to have paid off, looks like I might be getting work in the inference serving space.