I wouldn't really recommend going into any career just for "the money" but I'd especially recommend against it for law school. I see more bitter lawyers than I ever see in any other type of job.
Aside from the fact that it's a longer degree and you have licensing issues that make changing jobs exceedingly difficult, the only law jobs that would be comparable to the really high earning MBA jobs would be at top law firms like Skadden and even then, the top i-bankers are going to outearn you in a few years. Beyond that, the culture of law school is completely different than the small glimpses I've had into MBA life. Everyone is much much younger than in b-school so you get a lot of high school spillover effect (sad) and to top it off, it's a very solitary, not collaborative, course of study. There were times when I could go for a couple of days without talking to people and we were second only to the vet school in collecting on our (extremely generous) mental health benefits. This is not to say that I went to some backstabbing school-people would share their notes but everyone's half-hearted attempts at study groups in 1L mostly dissolved into 98% of the class getting their **** done by themselves. Finally, the practice of law is radically different from the sort of super academically rigorous/intellectual environment they marinate you in for 3 years, so I think a lot of people get pissed off by feeling like a sort of cog in the wheel after 3 years of case studies and intellectual exploration.
What I did love it for was the intellectual geekiness, the feeling of learning a whole new mindset and style of thinking and writing and the almost completed-a-marathon-like pride of having finished. Plus, I don't mind my job, it's just that I don't have a real passion for it.