It depends on what you're looking for. There can be significant variations among the initiatives at different schools, but the student profiles are strikingly similar. This is true every year at virtually every top school. For most applicants, virtually any top-tier MBA program will dramatically alter their career trajectory, so don't limit your choices during the application process. Apply to at least seven schools and then narrow your choices only after you've been admitted to more than one.
Let's run through the MBA class profile elements and clarify which are important and which aren't:
Average GMAT Score: At elite MBA programs, your GMAT score is the most important element of your candidacy. At top-tier business schools, the average score is now between 710 and 720. But you don't need to beat that average to be accepted. It should be obvious that half of the admitted candidates at top schools scored below it. So what number do you need to become a viable candidate? It varies by school and background, but applicants start becoming realistic once they break 600; and they become much more viable once they break 650. Ideally, you want to be within your target schools' "mid-80-percent" range, which for the top-tier schools starts at about 660.
Median GPA: Perhaps the most overrated statistic among MBA applicants. Applicants believe that a sub-par undergraduate GPA will keep them out of B-school, but that isn't true. Business schools are not terribly concerned with your undergrad performance. The only thing that concerns them is how you did in math classes (because they're afraid you might struggle with math-based courses, even though very few people do so). If you think your undergraduate math profile is weak, take a math class through a local extension school or do well on the math portion of the GMAT.
MBA Acceptance Rates: I like this stat. I think it conveys some important information — much more than median GPA does. In my opinion, acceptance rate is the best way to determine which school is the hardest to get into. Most people think Harvard is the most difficult admit, but it isn't. In fact, it's almost twice as easy to get into Harvard as it is to get into the most selective school. I'll let you figure out which school is actually the most selective.
Pop Quiz: Why is that school so much more selective than HBS?
Yield: By this measure, Harvard is the most selective business school on the planet. "Yield" is the percent of admitted applicants who accept the admit offer and enroll in the school (rather than accepting an admit offer from another program). Harvard generally dominates this statistic. About 89% of admitted students accept the offer. If nothing else, yield is an indication of what economists like to call perceived value.
Average Age: 27 or 28. Not much to say here, except that applicants who are over 40 years old are sometimes accepted, as are applicants straight out of undergrad. I don't find this stat to be very meaningful.
Work Experience: 0 to 20 months. Again, not a terribly meaningful statistic.
MBA Rankings: These are media products, not meaningful interpretations of MBA program quality. Still, in a broad sense they reflect perceptions of business schools, and perception is a valuable commodity. Take the rankings with a grain of salt, and don't read too much into the minor fluctuations that occur from year to year.