I tinted my windshield with Llumar Air 90. The reflections from the speaker grill are terrible, but they were terrible before the tint. I was afraid the tint would amplify ghosting or halo effects at night, but they all seem equally annoying before and after. I would say it doesn't make a difference as far as that goes.
I just wear my polarized sunglasses more often during the way to negate the reflections and I barely drive at night anyway.
I don't know if the car is a LOT cooler because of it, but I'm extremely comfortable (if not cold, my passengers all say it's too cold for them) when I keep the car at 70 - 72.
There were a few bubbles that showed up from dirt flecks in the worst spots though, so I'm having the tint company redo the windshield tint in two weeks. Just be prepared to find some imperfections in the tint, since the area they're tinting with a single piece of tint is huge.