AFAIK AWS is faster (although the difference may not be noticeable outside microbenchmarks) and they are fully offloading networking (and EBS) onto the NIC.
Replied to a sibling, but I believe our latency is currently coming in under theirs. Their largest/newest VMs advertise higher peak bandwidth than we do. The latency difference would certainly be most directly visible in microbenchmarks, although HPC applications and those relying on in-memory databases are also likely to see practical benefit.