Lets keep this brief.  This is a comfortable, accurate gaming mouse with a relatively short battery lifespan.  That being said, I love this mouse.I have a skinny hands with long fingers.  This mouse fits me perfectly.  There's a slight learning curve for the thumb buttons.  However, I was hitting them perfectly within the first hour.  The contour of the index finger buttons makes them especially familiar immediately.  I have always preferred the contour of a Logitech mouse so none of this surprises me.In terms of tracking it works great, as it should.  I use a Razer Exactmat speed surface so I predicted and received flawless tracking.  Unfortunately I haven't tested this on any other surface so I can't comment.Others feel the battery life is poor.  It seems to last three hours while gaming.  I couldn't care less.  Leaving the cord plugged into a USB port and sitting on the desk is simple.  I've always had a corded mouse so it doesn't upset me to play while it charges.Weight has been a posted concern.  I tested the mouse at the local electronics shop first and liked it.  I tended to prefer maxing the weight on my old G5.Finally I couldn't help but comment on a faulty review posted below.  The scroll wheel toggles to allow both free spinning and locking via a simple button smack dab in the middle of the mouse.  Great for switching weapons or zipping through PDFs.All in all this may have been a frivolous purchase as my old G5 was running like a champ.  Still I'm very pleased. The features are fantastic.  Setpoint works like a champ for profiling.  With all the extra buttons this mouse easily bests the G5 for any RPG.Update:  6 months later and I still enjoy the form and function of this mouse.  Changing jobs I've discovered yet another application for it.  With a [...] I take this into work everyday and really enjoy all the extra buttons for macro functions.  I've opted to stay corded at work so that I don't forget to bring the receiver home again.  With this beast and a few macros I've drastically cut my keystrokes for productivity applications.  Thanks Logitech! 

Question: How are battery?
Answer: relatively short battery lifespan