I recently reviewed a Saitek Obsidian mouse. The unit is wireless and works on the 2.4 GHZ frequency. The range of the mouse is 10 meters but I only tested it at 2 and it worked fine. The mouse comes with two battery backs that are about the size of 4 silver dollars. The weight of the battery pack is negligible and replacing them takes a few seconds.
Each pack takes two hours to charge and lasts ten. The mouse doesn’t have a wheel but has a about a one-inch touch sensitive strip where you might expect a wheel.
The strip takes getting used to but I find there is much more flexibility in how you can scroll on pages with this system.
For example if you are concerned about finger fatigue from excess scrolling, with the Obsidian mouse you just touch and hold for a moment at a time to scroll a number of lines.
The feel of the mouse is good but the ergonomic shape of a Microsoft mouse may be more comfortable for long periods.
I would recommend this mouse for anyone who wants the performance of a scroll wheel but wants more flexibility and/or has pain in their index finger from excess scrolling.