ixgbe vs ixgbevf Performance Differences

When deploying into AWS and wishing to make use of optimized networking (10Gbps), the AWS Documentation states that the ixgbevf drivers must be used. However, the drivers bundled with the EL6 and EL7 kernels is not compatible with the AWS SR-IOV implementation. One can use third-party ixgbevf drivers, but it's kind of painful. The other option is to ignore the AWS guidance and use the ixgbe drivers, instead.

I'm just wondering if anyone's benchmarked the performance - and associated instance-overhead - of using the Red Hat bundled ixgbe drivers or using the AWS-recommended ixgbevf drivers.

AWS also offers using Elastic Network Adapters, but that depends on running a 3.2+ kernel. That's fine for RHEL 7, but pretty much all of my customers are on or deploying on RHEL 6.