Originally Posted by pac0tac0
why the 400 instead of the 500?
I own two deathadder (standard and BE), two g400, two rat 5 and a MS sidewinder x8, so what i'm going to tell you is based on personal experience rather than the opinion of someone else.
The G500 have a better overall feel when in your mice, mostly because of the scroll wheel and the coating. The fact that the sensor have a little bit of acceleration and is not centered will make the mouse feel weird if you are used to a mouse with a ''good'' and well positioned sensor (like the G400). It personally does not bother me but it could be annoying to some.
The G500's lift off distance is lower than the G400's, but it is prone to a lift off bug where it will have an absurdly high lift off distance (you can RMA it if yours do that).
The G500 does not have mechanical side buttons. They do feel very mushy. I prefer the G400's side button as they make a nice click.
Both mouse can be used driverless.
The G500 have serious acceleration issues on black cloth (was really noticeable for me, much more than on my 9HD).
Originally Posted by raisinbun
They have very different grip, despite their similar look. G500 also got a hyper-scroll wheel with side scroll - not the ideal for gaming if you need middle click. Also the sensor difference as mentioned by zulk above.
The G500 also feature a tilt scroll wheel, which is much, much easier to use than the middle click on the G400. If you really need to use it you can just map your middle click on it.