Haven't seen any discussion of window tint lately (but I've read so many from the past, here and on TMC, that I got to the point of information overload!) Anyhow, I just had it done and I thought some might be interested.
My main concern was heat reduction and to a small extent I liked the look of gray tint with my gray car. But I didn't want to look like a gangster, and I didn't want noticeable interference with the view looking out.
I concluded there are many good products each with advantages of their own. Impossible to be all right or all wrong. So I went with Hüper mainly because their dealer in the area was close by, could do it right away, had a loaner for me, and they got what seemed to be legit reviews on yelp. The people who did my original paint protection only do tinting on Fridays and were booked out a month if I wanted a loaner.
My main concern was deciding between 30 (their lowest that's legal in WA) or 40. After going back and forth (literally, drove back there a few times and changed my mind on the day of installation, twice more) I decided on 40. They had to go to their other location to get some.
And then I went with 30!! Yikes. But it looks great, isn't gangster (i.e., can see into the car respectfully), the outward visibility is fine. They talked me into it, and I thanked them for it.
Anyhow, bottom line: I've never had tinted windows but a loaner from the original detailer/Xpel/Gtechniq did, and I was impressed with the heat reduction. In other cars, we've often had to spin the visors over to the side windows, even hang a towel from them. Not any more, I'm sure.
And the smokiness does indeed look pretty cool with my grey/grey wonder machine. So if anyone's considering it but isn't sure, I'm saying go for it. And 30, for me, is just right. (They say, however, that 30 for one manufacturer won't be exactly like that of another.)
BTW, for those who don't know, which included me till a few days ago, the numbers refer to the amount of light that passes through; so the lower, the number, the darker the tint. In WA you can go down to 25%. The guys who did it had about 5% on their cars, black as pitch, and haven't been hassled by cops. But it ain't for me.