USB issues with last Intel-based Mac EFI firmware updates: Part II

Following yesterday's news about problems faced by many users following installation of the EFI firmware, we received many reports confirming that it affects USB peripherals. In some cases, it affects only the time required for detecting plugged USB peripherals (USB external HD taking long time to mount, same for USB key), in other cases, all system resources seem to be devoted to the USB peripheral, leading to a "freeze-like" syndrome.
We can not conclude if it affects all type of USB peripherals, nor why syndromes are differents from one users to the other, but Apple should definitely better test updates before releasing them, as it will required new update to fix previously generated bugs. Mac users might delay applying updates in the future if such process resembles too much the Russian roulette.