M185: currently using this one, no fancy buttons, function, just every mouse.
Very comfort to hold, the arc lay nicely with palm and accurate cursor movement.
Invisible Optic which is very good because you won't flash by unwanted red/blue light
Cheap, long lasting battery?
Logitech claims 12 mths, so far been using for 4 mths, still going strong...
Its a good buy...definitely.
Recently bought a Logitech wireless mouse M705 however the seriously outlying sensor does not suit me. I really have difficulty trying pin point to location I wanted it to be...so decided to sell it.
Also Logitech does not show their mouse bottom in their web or you can't see them from mouse the packaging too...So I spend some times to gather some of the bottom pictures from the web.
Hope this helps...bcoz i believe some people are as particular as me about the sensor position.
Anywhere mouse M515