"Truely a revolutionary mouse."4.0 starson by Golden Helmet
Pros: Incredibly comfortable design, the scroll wheel is awesome, application switch wheel is new and much loved, just as responsive as a corded mouse, good battery life.
Cons: Scroll wheel seems a little flimsy to me, no on-the-fly DPI switch like the G7, the Search button is annoying, no interchangeable battery, slight startup lag, no middle mouse button replacement.
Summary: When I first heard of this mouse, my heart was filled with joy. When I first used this mouse, my hand was filled with joy.
This mouse is simply amazing. It fits comfortably in my hands (might have a problem if you have small hands though), being able to switch from normal to free spin is awesome, cordless is ALWAYS a plus (I REFUSE to use corded mice, and throw a fit if I'm forced to use one), it's every bit as responsive and precise as a corded mouse, it's got good battery life, I can go on and on.
The only complaints I have are rather small, especially when compared to it's positive attributes.
One thing that annoys me is the scroll wheel seems a little flimsy to me. I've had this mouse for about 3 months now, and it's always felt flimsy and weak, and lately it seems to have slowed down (when i flick it in free spin mode, it slows down faster than normal. May just be dust or dirt though).
I was spoiled by the G7 and it's on-the-fly DPI switch, and sadly Logitech didn't include that on this mouse. It's a shame, but tolerable.
The search button can, and probably will, drive you insane. I used to hit it accidentally a lot, so I disabled it in Logitech's software. Unless you really need it, I'd recommend you do the same too.
No interchangeable battery. If you forget to charge the battery one or two nights in a row, you're in for a bad day. But, on the plus side, it doesn't eat batteries like candy like the G7 did, so that's a good thing.
And last, we're all accustomed to clicking in our scroll wheel as an extra button in games, apps, etc. With this mouse, clicking the scroll wheel simply changes the wheel mode. So reconfigure you're games or whatever if you need to.
Switching to the more positive things, as I said above, it's a great mouse. It's precise. Battery life is great. I can't stress enough just how comfortable this mouse feels in you're hands. I'll just stop here before i start going on and on again.
Get this mouse. You won't regret it.