While I have been using the Performance MX for best part of a year, I have just received the MX Master. Below are my initial impressions after just a few minutes.
###Shape/Comfort It may be because I’ve been using the Performance MX for quite a while now, but I much prefer the shape over the MX Master. The “bump” on the Performance sits perfectly in the palm of my hand and supports in a natural position while the Master’s bump is too far forward and sits just in front of my forefinger knuckle.
###Scroll wheel The wheel on the Master has a slightly sharper click to each turn and the middle click can be felt throughout the whole mouse making it feel hollow. Again, I prefer the Performance over the Master. The infinite scroll button is now software controllable, good for those who will never use it but offers a disappointing tactile response compared to the Performance.
###Thumb buttons I’ve seen lots of complaint about the position and size of the back/forward buttons on the Master but I have to say that while they feel a little hard to hit at first they soon feel natural. The forward button has a slightly more prominent click to it and it’s easy to distinguish between the two. After switching back to the Performance the back/forward buttons seem too high up and out of the way. The gesture button remains the same although there is a more obvious click to the Master’s. I never used the Zoom button on the Performance so can’t really comment on that. Finally, the thumb wheel. It’s a great addition but the execution is flawed. While the scroll is nice and smooth the wheel is simply not pronounced enough to show it, I can’t scroll without my thumb rubbing against the other buttons making the experience a little awkward.
##A crippling issue One of the main attractions to the Master was the addition of bluetooth connectivity. I have a the logitech bluetooth keyboard with the smart switch stuff and it works very well. The bluetooth on the MX Master however has a crippling issue, every now and then the mouse becomes unresponsive for a second. I don’t know why this is happening but I’m not alone: