whats the difference ?
I'm no expert, but when I did kung fu (the teacher lady called it Wing Chun), the Karate classes looked more aggressive and seemed to require more physical exertion. Of course, these are only observations made upon walking past the classes, but it made my kung fu lessons seem a bit tame. The karate people even got to say the "HAH" thing they do on TV.
I considered switching, but the Karate teacher looked angry and I liked the people I met in kung fu (one of them liked Star Trek and looked suspiciously like a ninja).
I'm terrible at making comparisons