The narrow back area feels better than the slightly too wide rear of the Death Adder but again there's a problem, the mouse feels like a 3 wheeled car, the back isn't very stable compared with a 4 wheeler like the Death Adder. I know the analogy sounds silly but that's how it feels, the Lachesis feels far too easy to tip.
And for some reason it wont do 1000 Hz yet, it seems to only want to do 500 Hz. I suspect this will sort itself out. - Sorted itself out for no obvious reason.