actully yes I did.
the main character and a small subset of humanity use time dilation to stay near the same age as the rest of humanity “evolves”
to include - Health care with a max $ output then only palatine care including “super cannabis”
The final battles against the alien race were fought hand to hand in a energy damper field of some type
The aliens “win” but mankind is now mostly clones and homosexual but and offer to “switch” the forever war vets if they wish.
One of the vets even tries a relationship with one of the clones..and found it very unsatisfying.
Finally the vets and their sig others that have used time dilation to survive get a planet.. the rest of “humanity” allow this as a thank you and an experiment of sorts.
but its been nearly 20 years and I did not like it all that much so I might have a few minor points off.
Satisfied ?
The main characters didn't use the time dilation to stay the same age, the were subjected to the time dilation, with no input as to whether they wanted it or not.
The health care system took good care of workers, retired useless eaters barely get palliative care. (Sorta like where obamacare will end up.)
A major battle was fought inside a stasis field by combatants shielded from it in their suits.
The aliens don't "win", we can't breed fighters fast enough, and resort to clones, when our clones go up against their clones both sides recognize some sort of kinship (inexplicable to naturally bred humans) and cease fighting.
I only vaguely recall the born vs cloned tryst.
The vets are exiled to their own planet (they don't "get" a planet, they are once again, "subject to the needs of the service" and effectively deported from the new human race). They are kept around only as breeding stock for warriors against a possible future need. Hardly a thank you.
At least that was my take. Same basic facts, different spin.
Worth noting that Haldeman was a combat troop in Vietnam, and really didn't like fighting to loose (but then again neither did my WWII, Korea and Vietnam vet dad!)
Rather dystopic...