I have found a delay bug on the wired version of the Viper, at least on my unit. Once lifted, there is around 7 ms added delay for the following mouse click input, even after mouse being re-surfaced. Inconsistent delay makes it impossible to build up a reliable muscle memory. My hypothesis is that this behavior is caused by a bad implementation of so called "slam click" -fix. I would encourage people with this or any other Razer mice with optical switches, to test this issue on their unit and report it to the Razer Support in order to get it fixed.
This asynchronous LOD feature is amazing. But, I prefer to run without driver and that kills it.
Also, let profile led under the mouse is always red no matter what.
Another thing, it is more comfortable to lift with 1mm(lowest lod), and the movement it makes when I put the mouse down and lift is the best I've seen so far, it also tracks very well despite the lower lod.