Given the choices, I would pick the Roccat Kiro. I simply prefer smaller mice for fingertip or claw grips, and I'm also a fan of the older Avago ADNS sensors -- kudos to Roccat for choosing lower resolution PixArt/Avago sensors. I hate how other brands think that higher is always better... <_<
For those of you wondering, I believe the Kova 2015 uses a PixArt PMW3320 sensor, while the Kiro uses the older PixArt (Avago) ADNS-3050 sensor.
It would have been nice if the Kiro had a braided cable like the Kova does, or if the Kova would have removable thumb buttons like the Kiro does. I'm also curious as to why the smaller Kiro is 4 grams heavier than the Kova? @ROCCAT