By coincidence I was out on a '99 Dyna Sport on Friday. I'm sure the Fat Bob is better (I'd like to try one) but it would have to be a LOT better that Sport to be within a million miles of the V-Rod on any objective basis.
If you want a decent motorbike, then go V-Rod every time. If you want the Harley experience, then the Dyna has much more of it: it sounds the part, feels the part, hates turning, revs like a tractor and the handling on that 99 was apalling, but I think that was partly down to the comedy forks, and they have thicker ones now.
I like Dynas, they are fun. But I buy a motorcycle not JUST to have fun, but to have usable, safe, quick, practical transport. The V-Rod is usable, safe, quick, practical transport. I'd not want to find myself in a hurry to get home on a wet, dark night on unfamiliar roads on a Dyna.
Your call - enjoy, whichever you pick.