I think it is safe to say that the Cooler Master MM520 really did surpass its predecessors even though the shape has changed quite a bit, which might mean that you might not like this one even if you loved the old ones. The sensor in the older models was a big downside, but this has finally changed because the MM520 features one of the best optical sensors currently available, the PWM3360.

The build quality is exceptional for a mouse in this price segment as there is not a single rattle to be heard even when shaking the mouse vigorously. All materials used are very good with the exception of that silicone grip on the right side of the mouse. I honestly wouldn't say it's bad, but many people didn't like it. The default weight can be a downside for those who will not open up their mouse in order to remove the built-in weight. As far as I know, you will not void your warranty by doing so, but this may vary from retailer to retailer.

The PBT main buttons are a joy to put your fingers on, and the clicks are pretty good as well. I have seen some that are better, but I have definitely seen many that cannot even compare to these. They could be a tad lighter for my taste, but I prefer very light clicks. The scroll wheel is simply amazing for my taste, but the side buttons are a bit of a letdown. CM should have used higher-quality switches here.

The software is lightweight, doesn't consume many resources in the background, and is perfectly usable; I did not encounter any bugs at all. Its lighting customization options are great - the number of available options are almost too many. The profile switching can come in handy when playing different games, or even when working with different programs. You can also create macros to help you out in different situations.

There aren't many rivals for the MM520 on the market if you consider the combination of its unique shape and friendly price of $49.99. It is definitely a top choice, and I would gladly recommend it. Just make sure the shape suits you because it really is unusual.