Among the positive sides ...
The mouse is light and präzise.Ein lag is first imperceptible and configurable lighting especially makes sense if you can view the charge level, which then either at the loading station, the Mausad and on the palm rest with green / orange / red indicates the remaining charge. Each LED is individually configurable, you can choose between off, charge level, continuous light and pulsed light. The two latter with a free choice in software color. The charging station and the LED on the mouse wheel lights when activated, Permanently, the LED on the palmrest turns off as soon as the mouse is moved. The advertised proximity sensor (was so on the manufacturing side and partly in advertising) does not seem to. This LED is also the only one that does not affect quality. The mouse surface is white Vollkunstoff with soft-touch paint, where the logo remained unpainted. The illumination therefore looks a bit milky and not very homogeneous, it is also (subjectively!) A bit too garish.
The charging station is 10x16,5 cm (Mouse: 7x13 cm) and the illuminated outline a rather prominent item on the desk. Thanks to aluminum surface and unobtrusive lighting it looks classy, through its considerable weight (do not be weighed, but are 300+ g's loose) it is also non-slip on the table. The cargo area of the mouse is lowered so that it slips almost automatically in the correct loading position, the charging cable is sufficiently long with 2m, is charged via a USB port. Alternatively, the charging cable can be connected directly to the mouse. Then it does not bother, the high flexibility of the thin cable receives the "wireless feeling" for the most part.
The negative ...
First look and feel, the mouse is as already written on the surface and soft painted also on the sides or rubber coated. Paint is a tacky feel and non-slip, but unfortunately prone to fingerprints, so that the areas for finger and thumb rest shine greasy after a short use. In addition, the feel of the side mouse buttons does not fit entirely to the price category. These are like all unpainted parts executed in black plastic, which is errinnern on piano finish. The pity is that act primarily the right buttons for the ring finger klapperig. That goes also better show the thumb buttons, these are executed wobble-free and with a defined pressure point.
Now an important revenue stream, the function. The mouse and the charger function both not very stable. This applies both to the charge, as well as the use. From time to time either the mouse or the charging station depend on completely, so that the mouse off at the bottom and has to be turned back or the charger from the USB port must be disconnected. A system can not be seen, happened about 1-2 times per week.
Second weak point is the charge which does not always take place. The charger requires a USB port, which is also supplied with the computer in standby voltage (USB Charge, must be partially enabled in the BIOS). Unfortunately, it works well then not always, because I put the mouse several times at night to unload the station and in the morning it was then still. The USB2.0 port used is under tension, a trial basis attached USB hub with LED showed. A change to a USB3.0 port (at least double current compared to USB2.0) brought no change, except that there the top said hanger charger increasingly showed.
Conclusion: On the MSRP price tag were the time of purchase 160 currently (June '14) are not there much less. I probably paid thanks false pricing half, but the result is not necessarily satisfactory. Decisive for the purchase was the charging station, which unfortunately does not work stable. In addition, combined with the crash of mouse charging station can be the first Sensei as not necessarily recommend.
It remains to be determined whether this is a defect, which will then show after complaining to Amazon.
Update 1: Since about August 14, the mouse is used without the control software of SteelSeries. The stability has done quite well, hanger of mouse and charging cradle are gone massively (2x in the last quarter, was previously nearly a week). The charging problems have remained, the contacts on mouse cradle need regular pats, either by oxidation or whatever settles on the metal to be removed. With fingertip over it wipe suffices repeatedly inserting without wipe over it helps only sometimes. Sad for a mouse 140 (as of 04/15).
Update 08:04:16: The charger has after 12 months finally left the service, a charge is no longer made. Simple replacement through Amazon.
