This is mouse was bought to have something a little different that the Death Adder 2013 I own and have been using for a while now(this is also an amazing mouse if you do not want any more than the normal sets of buttons) and I love the DA, but for all the rpg's, mmo's, and even some of the programs I am running extra buttons would help. This is due to tenkeyless mini keyboard which has only 66 keys on the keyboard. So when I ordered this ordered with a bit of uncertainty due to the fact that I have not yet use or owned a wireless mouse that hasn't had its heaps of issues. Well this mouse has put all those fears to rest, there has been no lag to speak of, problems with connectivity is non existent, and the tracking and accuracy of the sensor is fantastic as other mice that I own with the same sensor. Now this mouse is on the big side, but it is also one of the most comfortable mice besides the DA 2013 that I have ever used let alone owned. It is for right hands only unfortunately to some people, but it is sculpted to git right hands well. Now, as far as build quality goes it is one of the most solid feeling and ergonomic mice I have come across from logitech or any other company, and I could recommend this mouse to gamer's and non-gamer's alike because of it's value, quality, and comfort. I highly recommend this mouse and the only things you have to remotely worry about are the fact that it is wireless, so you will need to change batteries eventually. They do however have some of the best battery life I have read of, and in two different modes you have performance mode=250 hrs of life, and endurance mode= is something 1300 hrs of life. It also has an indicator via the press of a side button letting you know how your battery life is low or not. Lastly the logitech software for this mouse(does not need to have software, but you cannot fully adjust each individual dpi setting without it) is some of the most intuitive and easy to use software I have seen for any pc peripheral which is really saying something.
So, as you can see if you are on the fence with buying this mouse then clearly, get off the fence and make the purchase it is a fantastic product.
Note for users: I personally believe you should purchase a non cloth gaming pad with a better gliding texture if you are buying this mouse to game with, and that is only because it is alower sensitivity setting mouse. I am currently using a new pad more like surface the Razer Sphex(only other thing I like from razer besides their mouse) but it is highly worth it for the combination. It is a surface that you stick to your desk and it is the width of a few pieces of paper, but do not let it scare you because when you place it down it is a great surface for any mouse.