I think that Topping must be done. Right now I am working on one plant that I have topped 2 times already, one of which was perfect (Still getting taller with 2 new colas growing every little bit). It's hard to explain. you can see what I'm talking about on my 420 thread. I will try to find out where I learned the "perfect" cut. . .

but ya, anyway, Top it! Even if you are not trying to clone it, in my opinion it turns out the potential of a plant (in my case it helps cause of my single female).