I need a desktop wireless mouse, under $60 [US].
It needs to be responsive, and comfortable/easy to use and *it must to have dpi "on-the-fly" adjustment*.
Good battery life is a definite plus.
I just got a Logitech Marathon Mouse M705 and like it except I cannot adjust the dpi setting without going into the software and adjusting the speed/acceleration. This is an inconvenience up with which I will not put.
I prefer a recommendation from personal experience, but I will accept links to multiple reviews of a product from qualified sources. Sites that have an unproven background are not helpful as they are very possibly shills for certain products.