what games are you playing?
i do not know the 402 but the g400s is considered to be one of the best mice for fps.
other "perfect" mice include the DeathAdder, Abyssus, Zowie FK1 / FK2 / EC-A / ZA, Steelseries Sensei / Rival / Kana, which are the primary.
there are also other mice with perfect 1:1 sensor implementation which however :
1. are from weird minor brands and support is not ideal / they fail more often
2. have unusual body shapes or are too heavy
3. (always an issue) bad drivers
such as corsair M65, Mionix Avior / Naos, logitech G502 ..
overclock.net has a nice list
http://www.overclock.net/t/1529102/the-ultimate-god-tier-mouse-list
consider this: mice today are becoming nearly perfect. even if you bought a "decent" tier mouse you would need to be MLG skill to actually get to the level where you notice your mouse is not perfect.
yeah you can still buy shit mice, even today (gigabyte M6800), but if you randomly pick a mouse by a gaming company, it will probably do well for you.
so it boils down to shape - find a mouse with a shape that suits your hand, and it will help a lot.
personally, i would recommend the FK series. they have a shell that is very close to the WMO / Intellimouse (still available on the market and a GREAT mouse) and a perfect 1:1 with nearly limitless acceleration / tracking.
actually, you should probably get an Intellimouse 3. It will be a meter by which to judge every other mouse.
