A dog is a dog, whether it's Bowser, the family mutt in the back yard, or Rin Tin Tin III sniffing for bombs for the army. Each one is an individual, and will be as unique as all the rest, regardless of whether he just keeps the floor in his doghouse from floating away, or whether he's kept busy searching for bodies in a bombed out building.
So far as I've noticed, there's no such thing as a military/LE dog with balls, though, so like any other sexually mutilated dog, he's likely to be disappointing in the sheets. Dunno if they routinely carve the pertinent parts out of females, so maybe they're different that way. I'd expect they do, since they don't want a dog - they want a predictable tool for whatever use it's being put to - and a bitch going into heat would likely fuck with that predictablilty hard enough that they'd probably want to cut out her girl-bits to make sure those evil hormones don't distract her from her work.
In short, LE/Military dogs are HIGHLY unlikely to make a decent sex partner, since it's almost a given that they're going to be sexually mutilated, AND because they're *VERY RARELY* farther than a few yards from their handler unless "on assignement". Either way, lotsa luck trying to get any significant amount of "playtime" with one.