OK, I've had mine for a few days now and the first thing I noticed is that it feels like a mouse should feel. In other words, it feels "normal" to me because I used MX518s for so many years in the past. With one exception, the top surface makes my hands sweat a little. Not too uncomfortable, but it's noticeable. Still, I think I'm adjusting to it. What's more, it may feel "normal" as I said earlier, but I know the bits and pieces inside have been updated and that it's actually improved over what the mouse used to be. But it also means it's right for the performance we are currently used to so that's a plus you may not ever notice but is there all the same.