On my Ram I had the front side windows matched to the factory rear windows, with the tint shop saying that was around a 20% tint. Also put a 5% strip along the top of the windshield. On my car, that I drive more often, I had 35% done on the sides and back along with the 5% windshield strip.
I think the 20% on my truck causes some visibility issues at night. When trying to make a sharp turn to the left onto a road with no street lights around or navigating around a dark parking lot it's hard to see out the windows. It was also hard to backup at night because you couldn't see very good out the side mirrors (which I corrected by adding additional reverse lights). On the car with 35% I rarely ever think the visibility at night is an issue, where as I regularly think it is with the 20% truck tint. To be honest I think the lighter 35% does just as good of a job with a reduction in glare from the sun as the 20% does, and if I had it to do over again would highly consider only doing 35% on the truck. I don't drive with the windows down very often now because I like the shade of the tint better than having them open. I really don't notice any big difference in heat build-up if either vehicle is parked outside. Both have a similar light gray interior.
In regards to ceramic tint, the main thing is that it does a better job of reducing UV. UV is not visible, and UV is not heat either....however a lot of shops have a display that tries to show that ceramic tint reduces heat. UV is the primary reason you get sun damage and fading of the interior. Though I will say that sun damage is not nearly as big of an issue on cars made within the last 20 years as compared to older ones. My last truck was 16 years old and spent most of it's life parked outside with no obvious sun damage on the interior. My tint shop offered ceramic but definitely didn't try to up sale me on getting it.
If you are not familiar with driving a tinted vehicle at night, my recommendation would be to drive around with a pair of sunglasses at night and see what you think. Somebody will probably jump my case for saying this, but what is the difference between this and driving around with tinted windows? In my opinion, looking through the 35% tint on my windows is about the same as looking out a non-tinted windows with sunglasses on. 20% is a little darker than most sunglasses.