I do re-read them as an adult. Frequently.
Heinlein's "juveniles," IMO, are among his best work. I wouldn't put "Rocket Ship Galileo" on top of the list, though.
It is interesting to see how many of Heinlein's predictions were accurate, and also which ones were way off the mark. The latter includes predictions of future computer technology. His starship pilots still used slide rules, and rocket guidance systems used actual physical mechanical parts like cams. To be fair, not many SF authors of the 1950s and 1960s saw microcomputing coming down the road.