The usual answer is "no".
Kids get so twisted up inside - pressure from both parents, pressure from other family members, pressures they face outside of the custody case (medical, psychiatric, school/learning, social issues, sex, drugs, etc.). They act out, they get sick, their existing problems get worse. Tons of studies discuss how the stress impacts kids for the rest of their lives.
Parents? They have their lives swabbed all over a gigantic microscope slide. Pretty unpleasant. I mean, who doesn't have something negative in their past or present? And on top of the emotional and financial stress, they get to have their heads shrunk repeatedly, not just by their therapists, but by forensic mental health professionals for use in court. Yeah, not fun.
Whatever the results, everyone's too burned out and too broke to do much except collapse after their cases end.
But let's look at this from another angle. The earlier, more traditional - now passe - view. Maybe there are winners. Not all the time, but sometimes.
Like in the documented child abuse and neglect cases, of course. Saving those kids from years of torment, well, that's a win for sure. No argument there.
Then there are the "shades of misery" cases, where, as a lawyer for the kids in one of my cases put it a long time ago, being with one parent was like living in black-and-white while being with the other was like living in technicolor. I'd say the vast majority of cases fall in this compartment. Tough to prove, but when the facts are finally pointing clearly in one direction and the kids end up with the technicolor parent), isn't that a "win"?
Now we get to the noisy, celebrity-choked gray zone of parental alienation claims. Experts pop up everywhere on this one, from the solid mental health pros who've been studying (and testifying about) this stuff for years, to the pissed-off parents whose latest rants are making the circuit on the Internet. Who knows who's really the alienator? Okay, sometimes the answer's kinda obvious. Not as often as you might think, though. Sometimes it boils down to: Who's kept the voice mails? Who retrieved the deleted parts of the hard drive? Who's got the most damaging text message records?
But assuming one's worse than the other - and someone usually is far worse (seriously, is any warring parent totally innocent?) - the facts will eventually be revealed. Hopefully, during the case. And then, isn't getting the kids away from the mega-toxic parent a good thing? A "win"?