After using one for almost 3 weeks. I must say this is the best wireless mouse I have used in terms of performance. It really does not have any noticeable lag and the battery last around 5 days on average for me.
However, I will be putting it up for sale due to ergonomics. I have been using the Deathadder for as long as I could remember and the Intellimouse before that. I just cannot get comfortable with the mouse and its affecting my aim in game.
If the shape is for you then you will not regret buying this mouse.
Such a shame but I know what you mean when a mouse doesn't feel right. I've tried various makes such as Razer and Roccat but personally I keep coming back to Logitech.
It's odd as whichever mouse I try, G700, G602, G502, G900 all feel great to me despite being very different shapes.