I have tried several things over the years, and decided it depends a little on what I am working on.
90's era: I used McGuire's Gold Class for a lot of stuff for a lot of years. Goes on super easy, takes some elbow grease though to really buff it out. lasted a couple months of sitting outside in WI in the summer, so I thought that was pretty good.
Older stuff with older paint I still use carnauba. Turtle still makes a really good product, back in the 80's we used Rain Dance in a tin, stuff seemed to last forever but I doubt that company is the same after 40 years. I have used Mother's carnauba also, it's fine, prefer Turtle. Mothers is easier to apply IMO.
My '13 Charger is all black, and I go through local gas station's car wash. I do NOT get the fancy shmancy premium bonus chemical wash, just a basic wash. I know the owner, he adds enough soap/chemical/acid to the wash water it cuts EVERYTHING off really well. Something about factory black paint on this car, I have tried to wax it a couple times and can;t even tell if it sticks, plus even without the water beads. not sure if the dealer or factory put something on when it was new or what. car is ten years old, lives in garage, but has gone through ten WI winters with basically no paint maint. besides auto wash and looks almost brand new yet. I did have the thing exterior/interior detailed when it was 3 years old. Maybe they put a fancy coating on then?
So I am not sure what I would use on a new, modern paint job even on an old car. new paints might just be different then old paints and take to products differently.
The guys in the Lexus forum have discussed just about every possible variation over the years. 
