Lag free wireless. Excellent button feel and travel. Comfortable shape with good anti-sweat finish. Perfect resistance on scroll wheel. Included USB extender cable for wireless dongle is a nice touch. Doesn't look tacky or garish, doesn't scream "GAMER" in public.

Back-heavy with AA alkaline; switch to a AAA rechargeable with an AA adapter and the mouse is perfectly balanced. Scroll wheel has rough edges. Only two "extra" buttons. Buttons only rated for 10 million clicks, so may not last.

Bought this as an on-the-go mouse for a gaming laptop, but ended up liking it so much (no lag!) that I'm using it on my primary desktop gaming rig - it edged out my G502 Hero. Switching out the AA cell for a AAA with an AA adapter fixes its back-heavy feeling. Because the buttons are only rated for 10 million clicks, they'll probably fail relatively quickly - all my Logitech mice have done this, and it is their biggest weakness. For the price, it get 5/5 stars. Will update with a new review if/when the buttons fail, after some longer term use, wear and tear.

- Crazy long battery life - Small compact - Lightweight - Perfect combo for a laptop for work and gaming on the go - Adjustable sensitivity with the center button - Durable Construction

-None, Literally none. Unless you have hands like Shaq, you should probably get a bigger mouse.

-I bought this mouse in combination with my laptop for school. I used this mouse everyday for school and the battery life in this thing is incredible. Went 6 months plus before i had to change out the battery. Even then with it flashing red it lasted a week before it finally gave out. I currently use this for work at the office as i bring it with me and it's been a great mouse. The front cover opens up where you can insert the usb dongle and change out the battery. This mouse is perfect for anyone on the go who wants to do work or gaming on it. I've recommended this mouse to multiple people.

great compact mouse

no weaknesses so far

long battery life - got in November and still on same battery fit - fits my hand perfectly, large hands, claw grip smooth - moves around my desk super easily easy of use - my 4 year old has mastered using it

Battery life.

Got this mouse as a gift for Christmas and I've already gone through 3 batteries and it lags quite a bit. I'm not a full time gamer and I generally turn the mouse power off to save battery life and that barely made a dent in the power consumption. I was expecting the battery life to be in line with what is written as part of the product description but it's far from what Logitech is advertising. YMMV.