Im mostly concerned about how its used day to day. And with the V8 im cruising around under 2000 rpm almost all the time. 40mph, is like 1800 rpm or something (I will take note when I take off this morning).
I doubt I really ever run it up to 3500 rpm. More cylinders means lower RPM in general.
I had a 3.5L V6 in my Infiniti and it was a fantastic motor (VQ35). Nice torque curve down low and was just very smooth. It was NA. ~300hp or something... it was great, but, even that mostly aluminum car was running 3k rpm most of the time on the highway in 5th gear. 3k rpm is not as quite or calm as 1800 rpm. It does make a difference.
Same with big trucks and tow vehicles, I've always loved the low rpm steady power delivery of a V8 (or V10!).
Its more than just numbers here, its the entire feel of the vehicle that is changed.
I think in my observation the engine will run 70 MPH at around 2100 RPM if I remember correctly. If I am doing 40 MPH and in typical fashion on flat or down hill conditions will switch into Sport and put it in 8th gear, I am able to run it at about 1100 RPM. Of course if there starts to be a slight gradient it will do fine but if it starts getting steeper I will switch to 7th gear and it only goes up to about 1500 I believe.
If we really want to come up with a speed to gear to rpm list I will play with it and report back for anyone who really wants to know what the new ratio is with the SCV6 and the 8 Speed vs the NAV8 and the 6 Speed.