The cost difference is huge. Modern compute is just so much bigger than one would think. Hurricane Electric is incredibly cheap too. And Digital Realty in the city are pretty good. The funny thing is that the Monkeybrains guys will make room for you at $75/amp but that isn't competitive when a 9654 based system pulls 2+ amps at peak.
Still fun for someone wanting to stick a computer in a DC though.
Networking is surprisingly hard but we also settled for the cheapo life QSFP instead of the new Cisco switches that do 800 Gbps that are coming. Great writeup.
One that would be fun is about the mechanics of layout and cabling and that sort of thing. Learning all that manually was a pain in the ass. It's not just written down somewhere and I should have done it when I was doing it but now I no longer am doing it and so can't provide good photos.