The Krona is just a bit more aggressive / efficient that a Superspeed. A nice everyday razor. Where it has the edge is that I find it much easier to use - the design of the doors makes finding the correct angle easy.
For me the Red Tip and Rocket HD are close to each other and a bit more aggressive than the Krona.
For me the Red Tip and Rocket HD are close to each other and a bit more aggressive than the Krona.