I put together a quick performance test to see how the response time of the AdvancedHMI driver compared to RSLinx, In this test I created as simple PLC program with a free running timer. Using AdvancedHMI I created a subscription to this timer tag with a PollRateOverride of 0 which would make it go as fast as it possibly could. I then allowed it to return 100 values. By subtracting the current value read with the last value read, it would give a reasonable time lapse. Over the 100 reads, I averaged the values. I then repeated the same using RSLinx. Here are the results:
Average Read Time for EthernetIPForCLXCom = 6.1ms
Average Read Time for RSLinx = 7.8ms
That equates to a 22% increase in performance when using AdvancedHMi verus RSLinx.