We're looking pretty good in AWS West 1a. The second thread you linked shows great performance from markdcorner's second load balancer -- the
https://forums.aws.amazon.com/servlet/JiveServlet/download/3... image -- vs the original ELB, which SpencerD@AWS describes as a custom ELB with some sort of customer-requested secret sauce (maybe some sort of "slow start" to some backend servers?). Indeed we have reached out to AWS a few times in the past and had some magic (at the time ciphers and removing SSL v2) done to our ELBs.
We have seen issues with performance on ELB which is why we originally went with TCP mode HAProxy on the edge of our stack to a cluster of STunnel servers, but again reliability was an issue here and our ELB performance with up to 10K rps looks great in benchmarks. Past 10K we are considering separate dispatchers behind a separate ELB. But at that point I am also tempted to, frankly, switch to our own metal.
Curious: are you comparing ELB performance vs High I/O EC2 instances (say m1.xlarge) open to the world?