Pros: I used this with a laptop and worked flawlessly until a couple weeks ago. Like many others the left click started double clicking. I play Age of Empires III a lot (yes..I know...just stuck on it for some reason) and so I'm not really suprised I used up the life cycle of the left clicker. No issues with connectivity.

Cons: I'm still a little surprised the left click started crapping out. You would think in this day and age, mice could near last forever.

Overall Review: I'm in a remote location overseas and could only buy a M305. This does not have Unifying software. Honestly, I'm not sure why ALL of their pieces don't have this. You could really dominate a market share with this feature. I will be mail ordering another Unifying device. BTW I have the their solar keyboard and it's pretty awesome. I'm in a room with no windows and poor lighting. Still charges with CFC type bulbs. A thought on the Unifying receiver. If you're having problems with the receiver on the backside of a computer, use an extension cable to bring it forward.