The CM Storm Quickfire is made by the same OEM as the Filcos, so it's of comparable build quality. Given that the Filco costs a lot more money and has one of the best reputations in the industry for quality, this is a great selling point for the CM Storm.
The Quicfire comes in two size and key options, one called the Rapid that does not come with a side number pad and another that does, thus giving an option to the purchaser of what size they would like.
The Vengeance K70 uses Cherry MX mechanical switches throughout the keyboard. They are also easily replaceable for those that would like to try out different switches or use a certain combination of them for gaming.
There are two analog knobs on the device with one controlling the backlighting brightness and the other the volume control. The analog sensors allow for more fine grained tuning of each and is not only more precise but more tactile. This makes for better control over normal keyboard keys for these...
The SidWinder has software implemented into the keyboard that allows for ant-ghosting, which helps with playing games when multiple keys are pressed at the same time. For what is a mid range gaming keyboard from Microsoft this is a pretty key feature that they have implemented for the price point.