Was looking for a replacement for my 555b, which for me is often choppy with their BT connection and begins after a good 2 years to have the problem of independent double clicks (probably inferior microswitch) the mouse. I really wanted the freewheeling Scrollradvariante because I feel awesome with the "fast scrolling" the. And I need a relatively flat mouse, because otherwise I get spasms in the wrist (M500 is a tried example. Much too high). The MX is because of the data fro the best replacement.
But not in practice, because occurs the much criticized at my copy on "Nachscrollen" scroll wheel when it is disconnected. Also by gently reciprocating mouse with scroll wheel dissolved moves the screen contents. All well-known problems that I never had, interestingly, at 555b. The left mouse button clacks in the MX considerably louder than anything I had known previously and has an ugly reduced stroke (probably manufacturing tolerance of any plastic parts / -graten), also in comparison with the right button. Overall, a frustrating experience, even in the face of no small price.
The Logitech "customer service", who wants to respond to email inquiries allegedly "within 48 hours", answered only after almost a week, with the (safe machine) assumption that the problem is now probably solved by themselves was. After I said no, answered another 2 days later some (presumably Irish or exiled Indian) Jennifer and told me that the 3-year Logitech warranty only last year after the warranty period assume (!) And I am in Meanwhile, the dealer (unfortunately, unfortunately, unfortunately, that's in my case the stupid market and this time not Amazon) to contact. Only when the dealer aushändige me a written confirmation that he was not prepared to accept the warranty / guarantee, I would like to address with this same certificate again at Logitech. Return the instrument somewhere, was impossible. - So one imagines the settlement of "3 years warranty" in practice, thank you very, Logitech, you understand it perfectly, streamline your processes and keep you annoying "customer service" from the neck ...!
Particularly ugly: I can not say "lick me, never again Logitech mice" because I * want * the fast scrolling with free scroll wheel. So probably again return to a new 555b - the successor to 557 seems the free scroll wheel is no longer considered to have.
Addendum dated 6.3.13:
+ I've now tried with an M525, which has an extremely fine-screened mouse wheel. This fast scrolling is possible, but not so "hyper fast" as in the mice with entkoppelbarem mouse wheel. Problem here: The middle click is performed using the mouse wheel itself, and not an extra key, and by the extremely smooth mouse wheel and the extremely weak screening can be the middle click practically not trip without turning the wheel unintentionally. This moves the mouse pointer, and it's very hard, "meet" the desired location via middle click to. Additional problem with my M525: I move the mouse horizontally, so the pointer moves a piece in the vertical, the motion is therefore "diagonally". In this combination an unusable for me device.
+ Another experiment I undertook with the T400 Touch Mouse. No more scroll wheel, but a remote elongated touch surface in the middle between the two mouse buttons, under which the front and back cover, respectively two microswitches. On the touch surface is the usual vertical scrolling as possible with a mouse wheel, but by horizontal wipe with your finger and horizontal effects. One can this swipe gesture can be interpreted in the browser as a request to forward or backward. The swiping to scroll control I really like, but you should not tend to wet fingers because any moisture on the surface generates a braking effect for the (no longer) sliding finger. For a tolerable I had to use the mouse, however, "pimp": The two regular mouse buttons are uncomfortable stiff. One reviewer described the possibility to take apart the mouse to cut the front part with a cutter between the mouse button areas a small and apparently unötige plastic nose. After that, the mouse clicks then much easier, and that is actually that. In addition, I had the side walls with fabric adhesive tape, cover, because the mouse is the side coated with a rough grooved rubber surface that is unpleasant to painful when held pressed down mouse for fingers. These two interventions, the mouse is now very decent. Hopefully there is no sweating in the summer and so then "Brake problems" on the touch surface.
