Here is an example of a plea deal resulting in a lenient sentence, albeit in North Carolina. I was a roommate with this guy for 6 months way back in my younger years, I was fresh out of law school and he was an up and coming computer network guy at a blue chip O&G. We both wanted to live close to our offices due to heavy work schedules.
Our roommate time was short at 6 months (he was devious I thought), and a few years later,... he marries a girl, they move to North Carolina, have two kids, and then the relationship sours and he kills her. He was convicted of murder one and received life in prison without parole, and then won his appeal, and then while facing a second trial took a plea deal, and he'll be out and about by about 2021, extradited to Canada.
Because it involved a person I know, a former roommate, I was glued to this trial. It was broadcast live over the internet.
There were flaws in the trial relating to technical evidence. The defence wanted to present an expert to debunk the evidence that the assailant had google mapped and zoomed in to the very spot his wife's body was eventually found, before she went missing. The judge did not allow the evidence. The judge was admittedly not technically inclined.
The court of appeal ruled the evidence should have been allowed to dispute whether the evidence from the hard drive showing the google maps search was reliable.
I've read the ruling in full and while the "expert" was in my view not reliable, his evidence probably should have been put to the test and let the jury decide after it is questioned by both sides.
The end result was before the second trial, the family was in agreement with a plea deal instead of a second trial. The assailant agreed to forever give up parental rights to the 2 children as part of the deal. He'll spend all told about 12 years in prison, maybe more, then come back to Canada around age 50.
I think he got off light, but his own life is also ruined. He's lost his children, will never have the wealth he coveted, and will forever be known as someone who killed his wife.
The CBC story:
http://www.cbc.ca/news/canada/edmont...wife-1.2773992
And the Dateline NBC show:
http://www.nbcnews.com/video/dateline/44208320
I was not happy about the plea deal but the family of the victim were quite accepting of the result, it appears. Sometimes the deal is better than the chance of not having any conviction.