I recently bought a few sparks from Micro Center for the exact same price and it comes with ConnectX-7 200Gbps inter-connectivity. Not sure how AMD feels it can charge exactly the same for less.
The differences are basically, sparks require ARM and sparks allow interconnects; so if you do have dreams of electric sheep to chain them together, you're not gonna get the AMD halo units.
But if you just want to putz around with a dev machine and do other things, not sure you'd want a spark.
They had it on sale last week for $3999, it will likely happen again. Also if you are willing to buy ASUS/Acer/MSI you can get them cheaper, in the same range as well. Those units are identical (mainboard/ram/chipset/connectivity), they only tend to differ in SSD being offered.
Only Asus from what I have seen. Acer/Dell units seem to run cooler than the Nvidia unit, by a noticeable margin. That said I bought the OEM units for the Gen 5 4TB SSD and the fact that it was on sale.