All the people who say, "I love his juveniles but hate the later stuff," are not exactly covering themselves with glory. The juveniles are very good, straightforward, escapist fiction. The later works (Starship Troopers from on) are where Heinlein really challenges the reader with deeper, interpretive stories and complex themes. Even the books written during his illness, though less carefully edited, offer far more subtlety and depth than the juveniles.
The juveniles are generally "safe" for the religious reader - nothing there to challenge orthodoxy - thus their overweighting in the general esteem of Free Republic readers.
His kid books rock, however.
Other great writers of juvenile science fiction include G. Harry Stine (aka "Lee Correy") and the incomparable H. Beam Piper. Read Piper's Space Viking and know the meaning of good science fiction.
I agree with the reader who labeled the last thick tomes his “dirty old man” phase.
He was either having old men have promiscuous sex with young cute sex kittens or they were taking showers. Too bad they weren’t cold showers.
I wasn’t particularly religious during the years I was a disappointed reader of these novels; but I was a pretty young thing who had been hit on too many times by older male employers and coworkers (one of whom physically assaulted me after I slapped him for grabbing my breast in the workplace) and I thought Heinlein was just writing out his wet dreams, not well crafted novels.