Is there a noticeable difference with 24p and 24f?
 

I noticed that Canon has gone the 24f route - what is the difference between the 24p and 24f and why didn't canon just go progressive like Panasonic?

There is absolutely no difference. There's more than one thread about this here and elsewhere. You might also want to go to the Canon site and read the white paper about it. The method of arriving at 24 fps progressive is different from different manufacturers.