A KVM VPS is better than an OpenVZ VPS.
Enterprise Grade KVM Managed VPS
KVM offers enterprise grade full virtualization. Every KVM VPS runs on its own dedicated kernel and file system. Hence it is not affected by another abusive VPS on the same hardware. Since it runs on its own dedicated resources, a KVM VPS offers high uptime and performance. tmzVPS offers managed KVM SSD VPS plans from $30/month and unmanaged KVM SSD VPS plans from $10/month.
Budget OpenVZ Managed VPS
OpenVZ is not a full virtualization technology. You still get full root access however an OpenVZ VPS runs on a shared kernel and file system. Since the resources are shared, an OpenVZ VPS may be affected by an abusive neighbor on the same hardware. Further, an OpenVZ VPS offers inferior performance and lesser uptime than a KVM VPS.