If you are a building a virtualization lab, a CI/CD pipeline for network configs, or an NFV deployment under 20 Gbps, then ne40ev800r011c00spc607b607qcow2 is indeed better — specifically better than R010, better than raw disk images, and better than earlier service packs.
Legacy .bin files allowed routing protocol processes (OSPF, IS-IS) to consume up to 95% CPU. The QCOW2 overlay enforces a cgroup limit, capping control-plane CPU at 75% during route flapping. This keeps SSH and SNMP responsive. ne40ev800r011c00spc607b607qcow2 better