Oh, no arguments here, my biggest argument with fimming is that sometimes I fuck up and miss my attempt to fuck up and miss properly, ending up with a regular top or clipping some leaves and leaving the top untouched. 
Though I tend to do it late, I want the plant to have time to get some nice vertical growth first. I’m not sure if it’s still called fimming when it’s done to a 3’ plant.
I think you can Fim whenever you want while vegging, so if I let them grow 5 sets of leaves, I can have 2 sets on the fimmed and 3 sets on the clone 1 to be removed and 2 to keep it going.
Not shure if it is fimming or topping…lol
I always shoot for a FIM but if it’s just a top I consider it a win anyway.
Sometimes when I FIM I end up with an extra little runt shoot I just end up clipping off.