Let me break it down for you:
some people like roses, some like tulips, some like red, some like blue, some like glossy some like mate...
so yeah, some will prefer GTA IV driving/damage (i'm this one) and some prefer GTA V driving/damage (you can be this one, and it's perfectly fine as well).
- GTA IV - bigger inertia, less tire grip and predictable collision results (GTA with closest to real world physics engine [just with over/undersized parameters])
- GTA V - fast paced, very low inertia. Allows for fast line switches and maneuvers, easy to pick and master. On off-road behaves somewhat badly, when the car seems to be tilting evidently on it's roof, it magically get's back on it's "feet". Thus, at least for me, after collisions with other cars or environment, the results are not completely intuitive.
When it comes to damage model, there is just NO excuse to prefer GTA V over GTA IV, let's be realistic here. (although i will get trashed in comments bellow for many reasons...)
this game would be PERFECT if it provided a choice to the player which driving physics he wants to use, but it does not.
everyone go here and vote, so we know what the majority of this community thinks.