1. Get the regular siberia v2 is enough, unless you go cyber cafe often then get the 7.1. The 7.1 soundcard doesnt make much improvement and the surround sound engine isnt as discreet as the 2nd generation soundcard (namely 9H and Elite soundcard)
2. If you love logitech then the rival is a much better choice since its an ergonomic right hand design
3. All qck are the same, just choose which size fits you nicely. Most people will find those ''limited edition'' design to be just right