Are you keeping surface on your VG. Looking at your overall arsenal, there is quite a bit of difference in the look of a VG and IQ solid, but cover strength is not much different. Not really sure what would fit in between. It really depends on how you are keeping the surface on the two balls. My VG was great, but only after it polished to the lane. Not so much in box condition. My IQ was great out of the box, and tamed down considerably when I let it polish to the lane, but is still a true benchmark ball.
I currently throw an IQ solid, Marvel Pearl, Cobalt Vibe, and Hammer Legend for my tournament arsenal.