Open Stack

It's KVM on Redhat with a fairly custom guest kernel, including 
optimized drivers for their network encapsulation. Auth is handled using 
their existing OAuth2.0 infrastructure.

As Matt said, their offering is fairly different from EC2 (and 
Openstack), competing more with compute-heavy providers, rather than 
amazon-like application-host offerings.

Their beta is currently only available to customers that they expect 
will run real jobs. Expect a phone call and a conversation about your 
application and current compute use before your organization gets an invite.

One neat thing about their product is that they provide dedicated 
spindles on ephemeral disks for instances with more than 2 cores.

Their user tooling looks very nice. There are probably features worth 
borrowing there.

-Paul