As someone who's driven on both (I swapped by OffRoad wheels for TRD which I'm currently on).
1) Weight savings at the wheel isn't trivial. It has a number of positive effects and only a couple negatives
Firstly, a vehicle with just a few lbs heaver on each wheel can be robbed as much as 5% from HP and Torque at the wheels. This is demonstrated and confirmed (youtube search it). Rotational mass and inertia mean more power is robbed and obviously fuel economy effected.
Secondly, rotating mass also has more burden on the braking system. This matters both NOW with how the brakes perform but more importantly, how long the pads and rotors last.
Thirdly, reducing unsprung weight improves suspension characteristics. Granted, on an SUV the effect is muted, but the way a tire reacts to imperfections in the road changes based on how heavy the wheel is. The lighter the unsprung mass, the more grip and quicker harmonics to return to grip when negotiating holes and bumps at speed.
Lighter wheels DOES however transfer road imperfections more. It makes sense that big heavy wheels and tires soak up things better, so lighter wheels will help you feel everything just a little more.
Lastly, I actually preferred the styling of the OR wheels, but for what it was going to cost to have them powdercoated black, I just decided I could buy new TRD wheels and sell the OEM (and that's what I did). Metal/Stainless just doesn't go well with an all black 4Runner. Looked goofy (to me). Other color schemes I'd have probably kept them.