Corehost is based in Somerville, Massachusetts. We have datacenter space in Marlborough, MA and Paris, France. Our customers are typically - but not exclusively - people and organizations who "know what they are doing" and/or care about software freedom.
Tools: corehost does not use proprietary software unless there is absolutely no alternative. We go pretty far in this respect: corehost is the first and only hosting provider worldwide to deploy servers that run coreboot, a free software BIOS replacement. Our servers and workstations run Debian or Ubuntu GNU/Linux. Our serial console servers are made by Opengear, and they are nearly 100% free software. The only remaining pieces of non-free software in our network are currently inevitable bits of low-level firmware in our computers, and the firmware of our switched PDUs.
Suppliers: where possible, we choose suppliers that share our commitment to free software. For instance, we do all our domain registrations via Gandi, who support Debian as well as other free software projects.