Calyraen builds both the hardware and the operating system in-house, at the same time, rather than assembling parts from other companies and installing software someone else made. The laptops (Stratus), desktops (Vantage), workstations (Atlas), and servers (Forge) all run Calyraen OS, which is designed alongside the machines it ships on. The idea is that the two are built to fit each other from the start.
That is the whole difference in plain terms. We are a new company, and everything in the store is currently marked OUT OF STOCK, so nothing can be purchased yet.
If you want the longer version of who we are, read /company/about. To browse what is being built, see /products. Questions? Open a ticket at /support.