Familiar Logitech quality, relatively expensive

Have been a few weeks, the M525 in the Office application. My positive and negative impressions:
+ Mouse is comparatively large for pure notebook use, rather compact for a desktop mouse - as an intermediate thing so. As usual wertig processed by Logitech.
+ The Unifying function through which you can connect several peripheral devices with a single nano receiver is practical and works flawlessly. However, it should, as soon as you use multiple devices with a receiver, the Unifying software installed (there of course free with Logitech).
+ Unlike (known to me) Bluetooth mice work this here (as well as wireless Logitech keyboards) without any delay (!) After the PC has been booted or after the mouse has been turned on manually using the small switch.
+ I know, does not hold any mouse with a battery pack for longer than 3 (!) Years. Whether that promise, I could not figure out naturally.
+ The Unifying receiver can soch in the battery compartment of the mouse perfectly safe.

- The mouse wheel is actually very finely milled and very very smooth (!). I feel more a disadvantage than an advantage. It is thus possible difficulties, the means (= mouse wheel) to use button, without moving the wheel up or down. In addition, the center button is pretty stiff.
- The mouse has a left / right function the mouse wheel. Ergonomic I find a thumb button - but then the mouse is suitable only for left or right handed. The sideways function requires the installation of the Logitech software ahead (another, as the Unifying software). By default, show the lateral buttons to page up / down function in the browser.
- The mouse is relatively heavy. It acts subjectively heavier than a Bluetooth MS-mouse for me. Of course, the vast majority of wireless mice are caused by the battery / batteries wesentluch heavier than wired devices.
- The mouse is expensive. She has only standard features, nothing special. Price / performance is safe with other mice (even from the same manufacturer) better. However, it has only limited choice, you want to use as a keyboard and mouse with only one receiver.