The big difference between 2011 and 2013 is that the parabolic rise took 3 months now instead of 2 months in 2011. Hence why I think the correction will also take longer.
The rise was a lot
more parabolic in 2011: that was a bigger bubble with greater volatility. When that bubble popped, the bearish trend became apparent fairly quickly and the price fell by about 92+% peak to trough. I don't see the same happening this time (unless Bitcoin fails altogether).
Duration does not equal depth.