I have a Logitech G5 mouse with optional weights. I read a study awhile ago (sorry I don't have a link) where it was found that the lighter the mouse the faster users were able to respond to on-screen stimuli. I guess that makes sense since there is less momentum to overcome. I was just curious if anyone had any insight into any benefits that adding weight might produce, or if it's just a matter of preference. I do use the mouse for FPS gaming btw. Thanks!