Supermicro is definitely a "you get what you pay for". We bought thousands of servers from their vertical integrations partners, had massive board and backplane problems. Took a few years but they eventually took back over $30 million dollars worth of servers, which were scrapped ultimately because the rework on them was so cost prohibitive. We lost $30M on that even after the $30M in good will refunds. Supermicro also has the lowest bios/efi/bmc/ipmi/redfish out of any vendor we have seen. Just low tier cheap ass shit by a company who can barely survive quarter to quarter without running some new scam on customers, investors, and even governments.
I haven't worked with anything at that scale, but the little bit that I was SuperMicro adjacent I was always unimpressed by the "fit and finish" of the entire experience, as compared to Dell and HP. (Having said that, the entire x86 commodity server experience is shitty anyway. I had a brief time, early in my career, when I did work with DEC Alpha machines. Man, they had their shit together. Stuff was expensive as sin, but stuff worked together and worked well. Build quality was tank-like.)
Pretty much the same experience (on a much smaller scale). And just open up one of their servers and compare the engineering to a Dell or HPE server. Anything that can be cheaped out is. Corrugated plastic for cooling air channels, FRU assemblies held in place with sheet metal screws, all very bargin basement.