I'm not sure there's really a reason anymore.  I think the IQ Tour is surviving on reputation alone, I don't see the effectiveness anymore.  I just recently drilled another one up and never get the chance to use it because something else is better on everything I see. 

I might still get an IQ tour one day but right now my DD Trick and DD offer a nice 1-2 punch on most house conditions. Just gotta quit being stubborn and switch or adjust my line when the lanes tell me