I'm at the same stage as you, so this is a little blind-leading-the-blind here, but I would say apply Early Decision to your first choice. You seem to be basing your decision purely on rankings, which is a little silly to do within the top 5-10. I worked as a support staffer at a V50 firm in NY, and they recruit heavily from all of the T14 schools. If they recruit from Yale more heavily than Harvard, it's only because CT is that much closer to NYC not because Yale is 1 and Harvard is 2. In fact, students from Columbia and NYU probably get to network more with them simply because of proximity.
So, figure out what your first choice is beyond who won the US News popularity contest this year. That's just lazy. If one criteria you have for a first choice is ranking, that's fine. You've narrowed it down to 14 schools. Now, where do you want to ultimately practice? What do you want to do after law school? In what type of student organizations do you want to participate? Think hard about what you want so that when your top choice asks you why they're your top choice, you have something a little better than "you're prestigious and my numbers fit your admissions stats".
Now, as for Early Decision vs. not? If you truly have a first choice, I think it is a good move. Schools like to be flattered, and there is nothing more flattering than for someone to make a promise like the Early Decision contract.
I applied to undergrad ED, got in and also was offered a generous scholarship package.
However, in the interest of full disclosure, I have decided against Early Decision for law school, and here's why...
I currently live in the city of a mid-T1 law school, and my husband will be here for the next 5 years because of his medical residency. My numbers are in the 75th percentile for this school. However, this city only has 1 or 2 international law firms and a handful of regional firms. I want to (a) practice in BigLaw, (b) practice in Chicago and (c) not accrue lots of debt from a school that makes it difficult to do (a) and (b). So, instead, I'm going to apply early, see if and where I get in as well as if and what scholarship packages I receive before deciding my absolute first choice.
In short, consider your priorities and go from there.