Glad I could help.
I think the IV makes a perfect Iron man for those who want "just one" as it marries many of the best elements between the III and VI.
I could have seen myself making the same decision if I didn't have any Iron Man figures. But, because I already have the DC MkIII, and I actually love it even with it's flaws and odd proportions, I decided to get the VI, again because it has more contrast from the III beyond just the better proportions with the triangle reactor.
I always find it interesting how various collectors choose what to get and what to pass on. I think I hit the biggest three factors in deciding between the IV and VI for many collectors. My guess is the desire to have the gantry captures a fourth group of collectors who would pick the IV either over or along with the VI.
Anyway, glad you feel good about what you decided. Welcome to the board.