"K'Nex was good, don't know if that still is."
I beg to differ. In my experience, K'Nex models fall to bits far more easily than lego models. My kids *play* with their lego models, but their K'nex models get built, played with briefly, and then returned to the box, never to see daylight again, because of their fragility.
I wish they'd play with their K'nex instead though, I got a huge lego technic bucket wheel excavator kit for christmas, and my daughter built most of it last week on the two days her school was closed for snow.