Hi Johnny,
This is another good question. First, for the differences in how Earl Decision and Early Action programs work (and knowing this is important since some of these programs produce a binding decision and some don't), check out an article we have from a few years back:
http://blog.powerscore.com/lsat/bid/200 ... s-the-deal. All of the descriptive info is accurate there, although the list at the bottom of the page about which school has which program is slightly dated (I'll have that updated over the next few days).
Second, different schools produce different results. Early Decision (ED), which yields a binding agreement for you to attend that school, has often been thought to increase your chances of being admitted. Why is that? Because, as you said, it makes you look committed, and literally you are saying that if you get accepted, that's the school you'll be attending. That's a valuable thing for a law school to know, because they spend a lot of time looking at things like applicant yield and incoming class revenue. But, not every school is the same. Some schools have aspects to their program that change the calculus, and so to some extent it depends on the particular school you are applying to. I've worked with a lot of applicants over the years, and so I've had many different opportunities to see these programs in action, and some give a solid increase in chances, some seem to have no effect, and others seem to actually decrease your chances if you are a borderline candidate. If you tell me exactly which school you are thinking about, I'd be happy to relay what my personal experience has been with applicants to that school.
Third, there are downsides to ED programs. If you are accepted, you are automatically locked in, and you have to take whatever financial aid package they give you. That means that you have no leverage for negotiating a better deal (in recent years, students have had a lot more leverage in improving their aid packages at various schools; ED takes that leverage away because you can't threaten to go to another school instead
). So, the financials involved play a role as well, and can impact your decision as to whether or not apply to a specific Early program.
Since it really depends on the school in question, if you can tell me the school(s) you are looking at, I'll tell you what I know about their program.
Thanks and I look forward to hearing back from you!