Raspberry Pi version 2 has changed playing rules between Linux boards. With raspberry Pi 2 here came faster CPU with four cores, RAM jumped to 1GB, so naturally we would expect faster speeds everywhere including GPIO. Joonas have ran several benchmarks to show the increase in numerical values, so we could make conclusions.
He run several common tests with available software libraries and GPIO access methods. Results actually look very promising as for almost all methods speed increased twice and more. For instance Python Rpi.GPIO based raw speed increased from 70kHz to 243kHz. Shell command driven IO became also 2.5 times faster. So this is great news for everyone who was struggling to the limits. For more info and benchmark tests go to GitHub.