I really don't like the city structure compared to GTA. It's like GTA knows how the make the world. The streets are big enough so that you can use your vehicles how you want. I constantly feel like the city streets are cramped in this one and that driving is a bit more of a pain than I want it to be. Maybe that's just something it takes time to get use to. But I also think its partially a design thing that rockstar is better at.
Yeah, I feel that Rockstar's world building is consistently the best in OWGs. The use of landmarks, color, building style are quite accomplished. I feel like I know where I am and which way I'm facing most of the time. But what I think you mean are player metrics for the size of vehicles, size and amount of NPC vehicles, and their placement on the streets at any time. I think they're spot-on there most times as well.
The feeling in GTA III and V when you're blowing down a major boulevard at full speed, and threading the gap between two cars stopped for the red light you're ignoring is... pretty awesome. It's a great way to lose cops on your tail.
I never managed to feel in control enough of the cars in IV to pull it off consistently, which lead to stress, which lead to me not trying it very often.
Driving in Saints Row has never been a high point; SR I and II, the cars handled as though they were on rails; no slop, no spin, no fishtail -- just varying degrees of acceleration. In SRtT and SR IV the physics improved but still never felt as polished as GTA.