Actually, I would say that Ringo's work actually surpasses Heinlein's (as far as the "mobile armor" concept--he goes Heinlein one or two better). Of course, Heinlein STILL takes the prize, as he devised the concept with science and technology concepts fifty years older than were/are available to Ringo.
Damn--I don't know how I am going to make it 'til the NEXT installment of Ringo's series comes out!!!!
I've just started reading the third volume. (No spoilers, please!) Did Ringo leave room for a fourth novel, or did he tie up all the Posleen loose ends?
Thanks!