These variations on the 2015 U.S. News law school rankings are based on the premise that what really matters is the "peer reputation" score. What accounts for a significant discrepancy between peer reputation and the overall rank? I'm guessing — and this is an educated guess based on 30 years of experience — it's about the aggressiveness with which the school selects students based on the hard numbers (LSAT score and GPA) and limits the size of the incoming class to control where the median LSAT and GPA go.
On this theory, the so-called "overrated" schools have played an aggressive numbers game that more than makes up for the lack of respect shown by the "peers." The so-called "underrated" schools are, I'm guessing, the ones that resist allowing U.S. News to push them to select students based on the hard numbers and have opted to build a student body out of accomplished, interesting individuals whose LSAT and GPA aren't so impressive.
The "peers" who are surveyed to get the "peer reputation" score are "law school deans, deans of academic affairs, chairs of faculty appointments and the most recently tenured faculty members" at all the law schools. How these people are expected to have accurate opinions of 194 law schools I have never understood. I've been among the surveyed peers a number of times, and I didn't think I had an accurate opinion about any of them. You're allowed to pick I don't know, but do you trust the power-wielders who do the survey to say they don't know? And if they think they know, do you trust them to base their knowledge on current information about the school? Worst of all, knowledge of the law schools is absurdly infected with knowledge of the very U.S. News ranking that annually reinfuses itself with endlessly recycled awareness of reputation.
For the opinion that reputation among academics is the only factor that should matter to prospective students, here's John Yoo. (For the record: My school has always done better on peer reputation than overall, though the difference isn't enough to put us on the most-underrated list.)