The problems I ran into were during installation, not during operation itself. If you can accept more up-front capital in the event of burning out some hardware (may not happen with server grade motherboards, I thought I fried my ASRock before but it was fine after tons of testing) and are willing to accept never opening up the machine for servicing beyond replacing the PCI-e card, it is fine.
If you're looking at these cases, you're likely looking for hotswap bays with as small of a footprint as possible, and after looking at hundreds of cases over a few years there's nothing else like it (it's why I bought it in the first place given how expensive they are). I believe these are modifications of Synology or QNAP NAS cases that were designed for custom small boards with low power and low cost (and low performance, unfortunately), so you could probably just use one of those SOHO NASes instead (although they run around $1400+ last I remember when I didn't spend even a thousand including my burned out motherboards - $200 case, $30 PSU, $40 HBA, $230 motherboard, $100 CPU, $130 ECC RAM). You'll have to sacrifice on either the hotswap bays or your footprint when using another case. If you're going to service more than one or two of these, I would suggest using rackmount machines anyway. This makes the USC-800 case fit a rather small market indeed.
If you're interested, I'm actually selling my USC-800 with everything but the drives if you still want to work with it. It's worked really well for me once it's running, but the installation itself is one I can't live with as someone that tinkers with their stuff all the time if it's custom-built (I buy Macs to never mod them as Lord Steve Jobs intended).