Overclockers Club published a review on the Zalman ZM-M600R Gaming Mouse
A quote from the article:
In the end I wasn't sold on the Zalman ZM-M600R gaming mouse. I can carry on the rant from the testing pages on my annoyance with the lack of buttons on this mouse, but I'm sure that's been stated enough throughout the review. It's apparently becoming a popular choice for some professional gamers, and it's hard to say if they honestly like them or, like most people, like to get free stuff. If they do actually like this lacking of buttons I won't put up a fight, we all have different tastes; many of you are in this small boat and won't even get to the end of the review because of it. It's fine. I'm not saying I want many buttons beneath my thumb, and I'm not saying every mouse should be designed for MMOs, but I will say it's time for mice to follow a standard of having the basic buttons. I will include the forward/back as basic buttons.Zalman ZM-M600R Gaming Mouse Review @ OCC