I bought the chassis + PSU and moved what at the time was an unraid setup. It was a super micro board with an E-2236 Xeon and ran fine before I switched it to Rocky+Cockpit. I can’t think of any reason you would have any issues with the full built system. The backplane is all direct connect and unraid had zero problems with it if that is your concern. Half my drives went to my HBA and the other half went to the onboard controller so I just put the drives on the same respective controller when I migrated. Way better than the cable nightmare of my previous tower case with a power and data cable to each drive.
I don’t even think about the cost now given the improvements this case provided. If you aren’t doing the full build, you just need to make sure you get the cabling right and consider some new fans.