Well, I have to say that my salesman influenced my decision by having me drive both on a twisty road.
The V6 has much better weight distribution, and the turn in was more immediate, and more comfortable.
The pick up in the flat area I live in is just fine with the V6.
Now, I have not driven a V8 Hyundai on the mountains of I-77 in West Virginia and Virginia, but I just took my V6 north and south on that road in the past week, and noted that compared to a previous 1998 Lexus GS400 (the V8 engine) the V6 did not climb the steeper hills at 80 mph with the same effortlessness. The V8 Lexus seemed to coast uphill.
Also, it seems that at high speeds, meaning at 80 miles an hour in the mountains, the Lexus had no degradation in mpg, but the V6 Hyundai drops from 25.5 mpg on flat lands at 80 mph, to 24.5 mpg in the mountains. The Lexus gave 24 mpg even in the mountains, and 24.5 on flat lands.
Aside from this unique situation, I would describe the V6 to be far better for every day driving. But I miss the way the V8 Lexus could pass other straining cars traveling uphill as though it were downhill.
In all fairness, the 2010 V6 Genesis corners better than the V8 Lexus ever did. The Lexus was never really a sports car, just a highway monster, and it was bulletproof reliable, too. My V6 Genesis is too new to gauge it's reliability (11,000 miles), but both cars had similar early problems. Interestingly, I did have to take my V6 to have the auto tilt
wheel repaired (recall is in) and the same was done for the Lexus. The Lexus also suffered corrosion of the closed door sensors, so that the auto lights wouldn't turn off til replaced. Finally, some yaw sensor was replaced in the Lexus. Interior lights didn't work in the Hyundai, and that was repaired under warranty, but the back up camera still works intermittently, and usually doesn't work when I really need it. The one time I got it in while not working they had no mechanics.
Too long a discussion, I know, but I will tell you that for hot-rodding around town, the V6 is more fun, no doubt. If you are taking highway trips, and like blowing the doors off of slow pokes, traveling at closing speeds side by side within 0.25 mph with their cruise controls on, and oblivious to those behind them, get the V8 and you will FLY thru the gaps before you're trapped. (At least, I hope the V8 owners are getting this experience).
