I bought the MX518 in 2006 for one of my first computer builds. A year ago it was perfectly in my hand. Button placement and placement felt like second nature. This new version feels and feels just like the one I bought in 2006. This mouse has survived 15 years of play, schoolwork and boredom. Hopefully this new one will last just as long if not longer. The only difference I can tell (besides the design and higher fidelity) is that the left and right click buttons are a bit louder and stiffer than the old one. However, this is more than likely due to 15 years of wear and tear.