Pros: Metal chassis
Cons: sluggish software
First thing I replaced was mouse- my Logitech Performance MX mouse died just 8 months after purchase, I used to have it's previous generation mouse and it was a way more durable, I'm very careful user and if mouse dies in less than a year, there must be something... Also Anywhere MX mouse died very quickly, some functions gone just after few months which is very disappointing as mouse was used mostly for my laptop on a rare occasions, swapped one on warranty and that also ended up very quickly.
About the M65- I have RGB version, which is slightly refreshed version and features RGB LEDs as well some slight design nuances. Not sure about very recent editions, but mine got that weird Corsair gaming logo instead of recently released Corsair new corporative logo. Some other products are updated with the new branding, but M65, no idea, so most likely you will find it with either the old logo or Corsair's weird gaming logo.
Build quality - this is where this mouse shines, absolutely best mouse I've ever had, metal chassis combined with poly carbonate outer, after 4 month of intensive usage it still looks and feels just like new, nothing has faded out (typical issue with Logitech where their logo fades out after first month). Also braided cable feels much more rugged and hopefully it will last much longer than one on my Logitech gaming mouse.
Buttons- I quite like feel of L and R click, other than that there is only dedicated sniper button and back/forward button. Ahh yeah, also DPI switch buttons on the top of the mouse. I don't need an MMO mouse, but I wouldn't mind few more buttons. Through the software you can change settings for buttons, if you don't need sniper button, you can assign any other option you want, same for back/forward buttons.
Software- and here is the only disappointment about this product- Corsair's software is a bit out of date, it has too many bugs and lags to be called a proper software for reputable company. In terms of functionality it supports everything you want, but it's so unreliable and sluggish you'd wish you never had to work with it. it randomly crashes, it forgets it's settings and other issues are just a small part of overall disappointed.
But, since software is just a small part of the whole deal, it can't harm otherwise excellent item, if Corsair had Logitech software, it would be the absolute killer combination! On the other hand, if I have to choose between software and hardware, I'll pick a hardware, I've been let down so many times by Logitech I can't even look a their items anymore. (Keyboard review coming soon )
Short conclusion- if you're looking for durable and reliable mouse, this is one to look for! It's not too fancy, it doesn't offer too many shiny buttons and Corsair software is a pain, but on the other hand, considering how many people work for Logitech and how little for Corsair, hands downs to them- they managed to built a fantastic mouse with only minor issues, and if we consider price difference, it's a no brainier, for some time I'm off Logitech products, could buy 10x Corsair mice for what I spent on Logitech products.