First off, if I was to rate the mouse on my impressions so far I've had it for about a week this is what I'd have to say. More updates if anything changes. Comfort-5/5 The thing fits my hand perfectly, that's why I got it. Buttons-4/5 The Email/IM notification buttons don't work, but I assaigned them to my Music folders and Firefox so it's all good. I really like how I can open music or a browser from my mouse. There are forward and back buttons and a side scrool weel. Yes, you push it to the side and it scrolls to the side! I love the volume controls up and down and mute are good for when my mom walks in while I play games. Battery-5/5 It goes into sleep mode which dramatically saves battery life. I use rechargeable batteries anyway so it doesn't matter. The mouse uses 2 AA batteries, but I've used only 1 in it without any problems. The extra weight is very easy to get used to. Laser Tracker-4.5/5 The thing is extremely sensitive. I play CS at 1.5 with mouse filtering instead of 5 (this is out of 20). Took me 4 or 5 days to get used to the sensitivity and another two to get my game back. Appearance-5/5 This thing is sexy to the max. I love it. I like how hard rubberish sides meet up with hard smooth plastic for the buttons. Everything about it is sleek and smooth. Comes with a 5-year warranty which is pretty good I guess, Logitech has a pretty good reputation for making quality mouses and keyboards so I'm not all too concerned.