I have the Gigabyte M6800, and have had it for a little over 2 years and haven't had any problems with it. Works just fine, I would highly recommend it for a budget gaming mouse. Its a pretty basic mouse, but it does feel comfortable and has very good dpi between the two settings. If I had any complaints about it, it would be that is a little on the light side. I would maybe preferred a little more weight to it, but definitely not a glaring defect. I also really like the finish on the mouse, as I am a heavy computer user and tend to "wear" out mice fairly quickly. I have a WoW steelseries mouse that I cannot even stand to have on my desk because the finish on it wore out so badly after a few months, the thing just looks horrible now.
Over all, I would say for the price, it would be hard to beat the M6800.
currently the best mouse in the 25 pound price range. i know its slightly more but the g400 is completely worth it... in its price bracket it punishes its competition on the whole and punches way above its weight for its price...
yes thats 5 pounds more but its worth it. every extra penny.