They don't use HyperVM anymore, they have moved to a paid one called SolusVM.http://hostingfu.com/article/fsckvps-servers-wipeout-reveals-lxlabs-hypervm-insecurity
One of the reasons why the creator of HyperVM hanged himself. Pretty shocking. He couldn't cope with it.
Santrex just cares about the money JMimic, it became opensource and therefore free so they (continued) using it. I dunno if they were using it while it was a paid service.
They don't use HyperVM anymore, they have moved to a paid one called SolusVM.
Googled it, it was FluidVMI don't think they used anything else other than HyperVM, and then SolusVM.