Given how many people are applying to law school, undergraduate GPA is almost as large of a factor as the LSAT when so many more folks with similar scores are applying.
I know that most of us are in our late 20's and into our early 30's. Most 0L's are in college or maybe one or two years out of college.
Here is the feeling that I get about admissions between Law vs. Business schools
1. Law schools will look very strongly at the undergraduate GPA, and to a much higher degree of scrutiny than business schools. Once we hit Top 10, like NYU, UPenn, Harvard, Stanford, etc., GPA's start to be scrutinized more, but even then, it's nowhere like it is in law school.
Take Yale University Law School, which is generally regarded as the best law school in the US. The median GPA is over 3.9 and the median LSAT is at 173 which is easily in the 99th percentile.https://officialguide.lsac.org/Release/SchoolsABAData/SchoolPage/SchoolPage_Info/ABA_LawSchoolData.aspx
Another thing to show you just how hard it is to get into Yale is by looking at a GPA/LSAT matrix, which it provides (spoken English makes me want to say they but we know that's not true). Out of 2,380 total applicants, out of 275 students who got a ticket to the promised land, only 63 admitted students had an LSAT under 170. Only one student got in with an LSAT below 160. With GPA, only three admitted students had a GPA of under 3.5. So basically, anyone with under a 170, and certainly under a 165 has basically no chance at Yale, and anyone with less than a 3.5 GPA has literally no chance at Yale. It is like this at most of the Top 14 Law Schools to a lesser extent where median GPA's still are well above 3.6 all across the board. At almost all these schools the median age of a 1L is 25 or less except for Northwestern, which is an anomaly due to their "business type" approach to law. https://officialguide.lsac.org/Release/SchoolsABAData/SchoolPage/SchoolPage_PDFs/LSAC_LawSchoolDescription/LSAC3987.pdf
For Business school, let's take Yale SOM, a Top 10 business school in the US. Average GMAT is at around 720 and average GPA is at a little above 3.5. http://mba.yale.edu/MBA/students/class_statistics.shtml
The 10th percentile of GPA was at 3.1 or so, but either way, if someone kicks ass on the GMAT with a 750 or more but has a 3.0 GPA or so, he still has some shot at a Top 10 school, where as with law school, they can almost say sayonara to a Top 14 considering that College grades are looked as strongly as they are. Even at the best US business schools (Stanford Harvard, etc), the GPA ranges are a bit wider than law schools at similarly ranked institutions.
2. Law schools prefer recommendations come from professors, though they understand it when someone is four years out of college or more, but they still would rather see that you have one from a professor if possible. In business school, they strongly discourage such LOR's.
3. The LSAT is a bigger mind game than the GMAT and it is more stressful. LSAT test takers will test in a room on pencil and paper with 40-100 more test takers and go through a period of over 2 hours before the first bathroom break. LSAT test takers must wait three weeks or so before getting their results. In addition, there is always talk about "the curve", or how many wrong questions someone can get in order to get the critical Top 14 median score of 170, as well as curves for 165 and 160. If someone retakes, the maximum limit is three times in any two year period. If someone wants to take it a fourth time in a two year period, he or she must ask LSAC for permission. Lastly, with pencil and paper tests, the LSAT is only offered four times a year, which only ratches up the stress for them. In addition to that, the testmaker tells you when you take the test. Generally speaking, most tests tell you to get to the test center at 8:30 or so in the morning, but the June test is in the afternoon.
GMAT test takers will take the test in a computer lab, with not too many other test takers, and some of them may be taking other tests, like the GRE, ASVAB, PRAXIS, Insurance licensing and others. There is a bathroom break after every section (roughly one an hour). GMAT test takers get their scaled scores immediately, and for retaking the test, it is once every 31 days, or close to once a month. It just costs $250 each time however... Test takers can take solace in the fact that they know they are getting a hard test no matter what, and if it's really hard, then that's a compliment. In terms of taking the test, test takers pick the date they want to take the test, and often, they can pick what time of day to take the test if it's available. With computer adaptive testing, the testmaker is more accommodating to the test taker, though most of the GMAT test times start at 8 AM and that sucks for me at least.
That's not to say that the GMAT is a breeze. We still gotta work for our scores. But I think our approach is a no-nonsense, and pragmatic approach to standardized testing, while the LSAT is not that way.